// VT100.js -- JavaScript based terminal emulator
// Copyright (C) 2008-2010 Markus Gutschke <markus@shellinabox.com>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2 as
// published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// In addition to these license terms, the author grants the following
// additional rights:
//
// If you modify this program, or any covered work, by linking or
// combining it with the OpenSSL project's OpenSSL library (or a
// modified version of that library), containing parts covered by the
// terms of the OpenSSL or SSLeay licenses, the author
// grants you additional permission to convey the resulting work.
// Corresponding Source for a non-source form of such a combination
// shall include the source code for the parts of OpenSSL used as well
// as that of the covered work.
//
// You may at your option choose to remove this additional permission from
// the work, or from any part of it.
//
// It is possible to build this program in a way that it loads OpenSSL
// libraries at run-time. If doing so, the following notices are required
// by the OpenSSL and SSLeay licenses:
//
// This product includes software developed by the OpenSSL Project
// for use in the OpenSSL Toolkit. (http://www.openssl.org/)
//
// This product includes cryptographic software written by Eric Young
// (eay@cryptsoft.com)
//
//
// The most up-to-date version of this program is always available from
// http://shellinabox.com
//
//
// Notes:
//
// The author believes that for the purposes of this license, you meet the
// requirements for publishing the source code, if your web server publishes
// the source in unmodified form (i.e. with licensing information, comments,
// formatting, and identifier names intact). If there are technical reasons
// that require you to make changes to the source code when serving the
// JavaScript (e.g to remove pre-processor directives from the source), these
// changes should be done in a reversible fashion.
//
// The author does not consider websites that reference this script in
// unmodified form, and web servers that serve this script in unmodified form
// to be derived works. As such, they are believed to be outside of the
// scope of this license and not subject to the rights or restrictions of the
// GNU General Public License.
//
// If in doubt, consult a legal professional familiar with the laws that
// apply in your country.

#define ESnormal        0
#define ESesc           1
#define ESsquare        2
#define ESgetpars       3
#define ESgotpars       4
#define ESdeviceattr    5
#define ESfunckey       6
#define EShash          7
#define ESsetG0         8
#define ESsetG1         9
#define ESsetG2        10
#define ESsetG3        11
#define ESbang         12
#define ESpercent      13
#define ESignore       14
#define ESnonstd       15
#define ESpalette      16
#define ESstatus       17
#define ESss2          18
#define ESss3          19

#define ATTR_DEFAULT   0x00F0
#define ATTR_REVERSE   0x0100
#define ATTR_UNDERLINE 0x0200
#define ATTR_DIM       0x0400
#define ATTR_BRIGHT    0x0800
#define ATTR_BLINK     0x1000

#define MOUSE_DOWN     0
#define MOUSE_UP       1
#define MOUSE_CLICK    2

function VT100(container) {
  if (typeof linkifyURLs == 'undefined' || linkifyURLs <= 0) {
    this.urlRE            = null;
  } else {
    this.urlRE            = new RegExp(
    // Known URL protocol are "http", "https", and "ftp".
    '(?:http|https|ftp)://' +

    // Optionally allow username and passwords.
    '(?:[^:@/ \u00A0]*(?::[^@/ \u00A0]*)?@)?' +

    // Hostname.
    '(?:[1-9][0-9]{0,2}(?:[.][1-9][0-9]{0,2}){3}|' +
    '[0-9a-fA-F]{0,4}(?::{1,2}[0-9a-fA-F]{1,4})+|' +
    '(?!-)[^[!"#$%&\'()*+,/:;<=>?@\\^_`{|}~\u0000- \u007F-\u00A0]+)' +

    // Port
    '(?::[1-9][0-9]*)?' +

    // Path.
    '(?:/(?:(?![/ \u00A0]|[,.)}"\u0027!]+[ \u00A0]|[,.)}"\u0027!]+$).)*)*|' +

    (linkifyURLs <= 1 ? '' :
    // Also support URLs without a protocol (assume "http").
    // Optional username and password.
    '(?:[^:@/ \u00A0]*(?::[^@/ \u00A0]*)?@)?' +

    // Hostnames must end with a well-known top-level domain or must be
    // numeric.
    '(?:[1-9][0-9]{0,2}(?:[.][1-9][0-9]{0,2}){3}|' +
    'localhost|' +
    '(?:(?!-)' +
        '[^.[!"#$%&\'()*+,/:;<=>?@\\^_`{|}~\u0000- \u007F-\u00A0]+[.]){2,}' +
    '(?:(?:com|net|org|edu|gov|aero|asia|biz|cat|coop|info|int|jobs|mil|mobi|'+
    'museum|name|pro|tel|travel|ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|' +
    'au|aw|ax|az|ba|bb|bd|be|bf|bg|bh|bi|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|' +
    'ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|cr|cu|cv|cx|cy|cz|de|dj|dk|dm|do|' +
    'dz|ec|ee|eg|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|' +
    'gm|gn|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|' +
    'ir|is|it|je|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|' +
    'lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|' +
    'mv|mw|mx|my|mz|na|nc|ne|nf|ng|ni|nl|no|np|nr|nu|nz|om|pa|pe|pf|pg|ph|' +
    'pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|' +
    'sj|sk|sl|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|' +
    'tp|tr|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|' +
    'yu|za|zm|zw|arpa)(?![a-zA-Z0-9])|[Xx][Nn]--[-a-zA-Z0-9]+))' +

    // Port
    '(?::[1-9][0-9]{0,4})?' +

    // Path.
    '(?:/(?:(?![/ \u00A0]|[,.)}"\u0027!]+[ \u00A0]|[,.)}"\u0027!]+$).)*)*|') +

    // In addition, support e-mail address. Optionally, recognize "mailto:"
    '(?:mailto:)' + (linkifyURLs <= 1 ? '' : '?') +

    // Username:
    '[-_.+a-zA-Z0-9]+@' +

    // Hostname.
    '(?!-)[-a-zA-Z0-9]+(?:[.](?!-)[-a-zA-Z0-9]+)?[.]' +
    '(?:(?:com|net|org|edu|gov|aero|asia|biz|cat|coop|info|int|jobs|mil|mobi|'+
    'museum|name|pro|tel|travel|ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|' +
    'au|aw|ax|az|ba|bb|bd|be|bf|bg|bh|bi|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|' +
    'ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|cr|cu|cv|cx|cy|cz|de|dj|dk|dm|do|' +
    'dz|ec|ee|eg|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|' +
    'gm|gn|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|' +
    'ir|is|it|je|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|' +
    'lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|' +
    'mv|mw|mx|my|mz|na|nc|ne|nf|ng|ni|nl|no|np|nr|nu|nz|om|pa|pe|pf|pg|ph|' +
    'pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|' +
    'sj|sk|sl|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|' +
    'tp|tr|tt|tv|tw|tz|ua|ug|uk|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|' +
    'yu|za|zm|zw|arpa)(?![a-zA-Z0-9])|[Xx][Nn]--[-a-zA-Z0-9]+)' +

    // Optional arguments
    '(?:[?](?:(?![ \u00A0]|[,.)}"\u0027!]+[ \u00A0]|[,.)}"\u0027!]+$).)*)?');
  }
  this.getUserSettings();
  this.initializeElements(container);
  this.maxScrollbackLines = 500;
  this.npar               = 0;
  this.par                = [ ];
  this.isQuestionMark     = false;
  this.savedX             = [ ];
  this.savedY             = [ ];
  this.savedAttr          = [ ];
  this.savedUseGMap       = 0;
  this.savedGMap          = [ this.Latin1Map, this.VT100GraphicsMap,
                              this.CodePage437Map, this.DirectToFontMap ];
  this.savedValid         = [ ];
  this.respondString      = '';
  this.statusString       = '';
  this.internalClipboard  = undefined;
  this.reset(true);
}

VT100.prototype.reset = function(clearHistory) {
  this.isEsc                                         = ESnormal;
  this.needWrap                                      = false;
  this.autoWrapMode                                  = true;
  this.dispCtrl                                      = false;
  this.toggleMeta                                    = false;
  this.insertMode                                    = false;
  this.applKeyMode                                   = false;
  this.cursorKeyMode                                 = false;
  this.crLfMode                                      = false;
  this.offsetMode                                    = false;
  this.mouseReporting                                = false;
  this.printing                                      = false;
  if (typeof this.printWin != 'undefined' &&
      this.printWin && !this.printWin.closed) {
    this.printWin.close();
  }
  this.printWin                                      = null;
  this.utfEnabled                                    = this.utfPreferred;
  this.utfCount                                      = 0;
  this.utfChar                                       = 0;
  this.color                                         = 'ansi0 bgAnsi15';
  this.style                                         = '';
  this.attr                                          = ATTR_DEFAULT;
  this.useGMap                                       = 0;
  this.GMap                                          = [ this.Latin1Map,
                                                         this.VT100GraphicsMap,
                                                         this.CodePage437Map,
                                                         this.DirectToFontMap];
  this.translate                                     = this.GMap[this.useGMap];
  this.top                                           = 0;
  this.bottom                                        = this.terminalHeight;
  this.lastCharacter                                 = ' ';
  this.userTabStop                                   = [ ];

  if (clearHistory) {
    for (var i = 0; i < 2; i++) {
      while (this.console[i].firstChild) {
        this.console[i].removeChild(this.console[i].firstChild);
      }
    }
  }

  this.enableAlternateScreen(false);

  var wasCompressed                                  = false;
  var transform                                      = this.getTransformName();
  if (transform) {
    for (var i = 0; i < 2; ++i) {
      wasCompressed                  |= this.console[i].style[transform] != '';
      this.console[i].style[transform]               = '';
    }
    this.cursor.style[transform]                     = '';
    this.space.style[transform]                      = '';
    if (transform == 'filter') {
      this.console[this.currentScreen].style.width   = '';
    }
  }
  this.scale                                         = 1.0;
  if (wasCompressed) {
    this.resizer();
  }

  this.gotoXY(0, 0);
  this.showCursor();
  this.isInverted                                    = false;
  this.refreshInvertedState();
  this.clearRegion(0, 0, this.terminalWidth, this.terminalHeight,
                   this.color, this.style);
};

VT100.prototype.addListener = function(elem, event, listener) {
  try {
    if (elem.addEventListener) {
      elem.addEventListener(event, listener, false);
    } else {
      elem.attachEvent('on' + event, listener);
    }
  } catch (e) {
  }
};

VT100.prototype.getUserSettings = function() {
  // Compute hash signature to identify the entries in the userCSS menu.
  // If the menu is unchanged from last time, default values can be
  // looked up in a cookie associated with this page.
  this.signature            = 3;
  this.utfPreferred         = true;
  this.visualBell           = typeof suppressAllAudio != 'undefined' &&
                              suppressAllAudio;
  this.autoprint            = true;
  this.softKeyboard         = false;
  this.blinkingCursor       = true;
  if (this.visualBell) {
    this.signature          = Math.floor(16807*this.signature + 1) %
                                         ((1 << 31) - 1);
  }
  if (typeof userCSSList != 'undefined') {
    for (var i = 0; i < userCSSList.length; ++i) {
      var label             = userCSSList[i][0];
      for (var j = 0; j < label.length; ++j) {
        this.signature      = Math.floor(16807*this.signature+
                                         label.charCodeAt(j)) %
                                         ((1 << 31) - 1);
      }
      if (userCSSList[i][1]) {
        this.signature      = Math.floor(16807*this.signature + 1) %
                                         ((1 << 31) - 1);
      }
    }
  }

  var key                   = 'shellInABox=' + this.signature + ':';
  var settings              = document.cookie.indexOf(key);
  if (settings >= 0) {
    settings                = document.cookie.substr(settings + key.length).
                                                   replace(/([0-1]*).*/, "$1");
    if (settings.length == 5 + (typeof userCSSList == 'undefined' ?
                                0 : userCSSList.length)) {
      this.utfPreferred     = settings.charAt(0) != '0';
      this.visualBell       = settings.charAt(1) != '0';
      this.autoprint        = settings.charAt(2) != '0';
      this.softKeyboard     = settings.charAt(3) != '0';
      this.blinkingCursor   = settings.charAt(4) != '0';
      if (typeof userCSSList != 'undefined') {
        for (var i = 0; i < userCSSList.length; ++i) {
          userCSSList[i][2] = settings.charAt(i + 5) != '0';
        }
      }
    }
  }
  this.utfEnabled           = this.utfPreferred;
};

VT100.prototype.storeUserSettings = function() {
  var settings  = 'shellInABox=' + this.signature + ':' +
                  (this.utfEnabled     ? '1' : '0') +
                  (this.visualBell     ? '1' : '0') +
                  (this.autoprint      ? '1' : '0') +
                  (this.softKeyboard   ? '1' : '0') +
                  (this.blinkingCursor ? '1' : '0');
  if (typeof userCSSList != 'undefined') {
    for (var i = 0; i < userCSSList.length; ++i) {
      settings += userCSSList[i][2] ? '1' : '0';
    }
  }
  var d         = new Date();
  d.setDate(d.getDate() + 3653);
  document.cookie = settings + ';expires=' + d.toGMTString();
};

VT100.prototype.initializeUserCSSStyles = function() {
  this.usercssActions                    = [];
  if (typeof userCSSList != 'undefined') {
    var menu                             = '';
    var group                            = '';
    var wasSingleSel                     = 1;
    var beginOfGroup                     = 0;
    for (var i = 0; i <= userCSSList.length; ++i) {
      if (i < userCSSList.length) {
        var label                        = userCSSList[i][0];
        var newGroup                     = userCSSList[i][1];
        var enabled                      = userCSSList[i][2];
      
        // Add user style sheet to document
        var style                        = document.createElement('link');
        var id                           = document.createAttribute('id');
        id.nodeValue                     = 'usercss-' + i;
        style.setAttributeNode(id);
        var rel                          = document.createAttribute('rel');
        rel.nodeValue                    = 'stylesheet';
        style.setAttributeNode(rel);
        var href                         = document.createAttribute('href');
        href.nodeValue                   = 'usercss-' + i + '.css';
        style.setAttributeNode(href);
        var type                         = document.createAttribute('type');
        type.nodeValue                   = 'text/css';
        style.setAttributeNode(type);
        document.getElementsByTagName('head')[0].appendChild(style);
        style.disabled                   = !enabled;
      }
    
      // Add entry to menu
      if (newGroup || i == userCSSList.length) {
        if (beginOfGroup != 0 && (i - beginOfGroup > 1 || !wasSingleSel)) {
          // The last group had multiple entries that are mutually exclusive;
          // or the previous to last group did. In either case, we need to
          // append a "<hr />" before we can add the last group to the menu.
          menu                          += '<hr />';
        }
        wasSingleSel                     = i - beginOfGroup < 1;
        menu                            += group;
        group                            = '';

        for (var j = beginOfGroup; j < i; ++j) {
          this.usercssActions[this.usercssActions.length] =
            function(vt100, current, begin, count) {

              // Deselect all other entries in the group, then either select
              // (for multiple entries in group) or toggle (for on/off entry)
              // the current entry.
              return function() {
                var entry                = vt100.getChildById(vt100.menu,
                                                              'beginusercss');
                var i                    = -1;
                var j                    = -1;
                for (var c = count; c > 0; ++j) {
                  if (entry.tagName == 'LI') {
                    if (++i >= begin) {
                      --c;
                      var label          = vt100.usercss.childNodes[j];

                      // Restore label to just the text content
                      if (typeof label.textContent == 'undefined') {
                        var s            = label.innerText;
                        label.innerHTML  = '';
                        label.appendChild(document.createTextNode(s));
                      } else {
                        label.textContent= label.textContent;
                      }

                      // User style sheets are numbered sequentially
                      var sheet          = document.getElementById(
                                                               'usercss-' + i);
                      if (i == current) {
                        if (count == 1) {
                          sheet.disabled = !sheet.disabled;
                        } else {
                          sheet.disabled = false;
                        }
                        if (!sheet.disabled) {
                          label.innerHTML= '<img src="enabled.gif" />' +
                                           label.innerHTML;
                        }
                      } else {
                        sheet.disabled   = true;
                      }
                      userCSSList[i][2]  = !sheet.disabled;
                    }
                  }
                  entry                  = entry.nextSibling;
                }

                // If the font size changed, adjust cursor and line dimensions
                this.cursor.style.cssText= '';
                this.cursorWidth         = this.cursor.clientWidth;
                this.cursorHeight        = this.lineheight.clientHeight;
                for (i = 0; i < this.console.length; ++i) {
                  for (var line = this.console[i].firstChild; line;
                       line = line.nextSibling) {
                    line.style.height    = this.cursorHeight + 'px';
                  }
                }
                vt100.resizer();
              };
            }(this, j, beginOfGroup, i - beginOfGroup);
        }

        if (i == userCSSList.length) {
          break;
        }

        beginOfGroup                     = i;
      }
      // Collect all entries in a group, before attaching them to the menu.
      // This is necessary as we don't know whether this is a group of
      // mutually exclusive options (which should be separated by "<hr />" on
      // both ends), or whether this is a on/off toggle, which can be grouped
      // together with other on/off options.
      group                             +=
        '<li>' + (enabled ? '<img src="enabled.gif" />' : '') +
                 label +
        '</li>';
    }
    this.usercss.innerHTML               = menu;
  }
};

VT100.prototype.resetLastSelectedKey = function(e) {
  var key                          = this.lastSelectedKey;
  if (!key) {
    return false;
  }

  var position                     = this.mousePosition(e);

  // We don't get all the necessary events to reliably reselect a key
  // if we moved away from it and then back onto it. We approximate the
  // behavior by remembering the key until either we release the mouse
  // button (we might never get this event if the mouse has since left
  // the window), or until we move away too far.
  var box                          = this.keyboard.firstChild;
  if (position[0] <  box.offsetLeft + key.offsetWidth ||
      position[1] <  box.offsetTop + key.offsetHeight ||
      position[0] >= box.offsetLeft + box.offsetWidth - key.offsetWidth ||
      position[1] >= box.offsetTop + box.offsetHeight - key.offsetHeight ||
      position[0] <  box.offsetLeft + key.offsetLeft - key.offsetWidth ||
      position[1] <  box.offsetTop + key.offsetTop - key.offsetHeight ||
      position[0] >= box.offsetLeft + key.offsetLeft + 2*key.offsetWidth ||
      position[1] >= box.offsetTop + key.offsetTop + 2*key.offsetHeight) {
    if (this.lastSelectedKey.className) log.console('reset: deselecting');
    this.lastSelectedKey.className = '';
    this.lastSelectedKey           = undefined;
  }
  return false;
};

VT100.prototype.showShiftState = function(state) {
  var style              = document.getElementById('shift_state');
  if (state) {
    this.setTextContentRaw(style,
                           '#vt100 #keyboard .shifted {' +
                             'display: inline }' +
                           '#vt100 #keyboard .unshifted {' +
                             'display: none }');
  } else {
    this.setTextContentRaw(style, '');
  }
  var elems              = this.keyboard.getElementsByTagName('I');
  for (var i = 0; i < elems.length; ++i) {
    if (elems[i].id == '16') {
      elems[i].className = state ? 'selected' : '';
    }
  }
};

VT100.prototype.showCtrlState = function(state) {
  var ctrl         = this.getChildById(this.keyboard, '17' /* Ctrl */);
  if (ctrl) {
    ctrl.className = state ? 'selected' : '';
  }
};

VT100.prototype.showAltState = function(state) {
  var alt         = this.getChildById(this.keyboard, '18' /* Alt */);
  if (alt) {
    alt.className = state ? 'selected' : '';
  }
};

VT100.prototype.clickedKeyboard = function(e, elem, ch, key, shift, ctrl, alt){
  var fake      = [ ];
  fake.charCode = ch;
  fake.keyCode  = key;
  fake.ctrlKey  = ctrl;
  fake.shiftKey = shift;
  fake.altKey   = alt;
  fake.metaKey  = alt;
  return this.handleKey(fake);
};

VT100.prototype.addKeyBinding = function(elem, ch, key, CH, KEY) {
  if (elem == undefined) {
    return;
  }
  if (ch == '\u00A0') {
    // &nbsp; should be treated as a regular space character.
    ch                                  = ' ';
  }
  if (ch != undefined && CH == undefined) {
    // For letter keys, we automatically compute the uppercase character code
    // from the lowercase one.
    CH                                  = ch.toUpperCase();
  }
  if (KEY == undefined && key != undefined) {
    // Most keys have identically key codes for both lowercase and uppercase
    // keypresses. Normally, only function keys would have distinct key codes,
    // whereas regular keys have character codes.
    KEY                                 = key;
  } else if (KEY == undefined && CH != undefined) {
    // For regular keys, copy the character code to the key code.
    KEY                                 = CH.charCodeAt(0);
  }
  if (key == undefined && ch != undefined) {
    // For regular keys, copy the character code to the key code.
    key                                 = ch.charCodeAt(0);
  }
  // Convert characters to numeric character codes. If the character code
  // is undefined (i.e. this is a function key), set it to zero.
  ch                                    = ch ? ch.charCodeAt(0) : 0;
  CH                                    = CH ? CH.charCodeAt(0) : 0;

  // Mouse down events high light the key. We also set lastSelectedKey. This
  // is needed to that mouseout/mouseover can keep track of the key that
  // is currently being clicked.
  this.addListener(elem, 'mousedown',
    function(vt100, elem, key) { return function(e) {
      if ((e.which || e.button) == 1) {
        if (vt100.lastSelectedKey) {       
          vt100.lastSelectedKey.className= '';
        }
        // Highlight the key while the mouse button is held down.
        if (key == 16 /* Shift */) {
          if (!elem.className != vt100.isShift) {
            vt100.showShiftState(!vt100.isShift);
          }
        } else if (key == 17 /* Ctrl */) {
          if (!elem.className != vt100.isCtrl) {
            vt100.showCtrlState(!vt100.isCtrl);
          }
        } else if (key == 18 /* Alt */) {
          if (!elem.className != vt100.isAlt) {
            vt100.showAltState(!vt100.isAlt);
          }
        } else {
          elem.className                  = 'selected';
        }
        vt100.lastSelectedKey             = elem;
      }
      return false; }; }(this, elem, key));
  var clicked                           =
    // Modifier keys update the state of the keyboard, but do not generate
    // any key clicks that get forwarded to the application.
    key >= 16 /* Shift */ && key <= 18 /* Alt */ ?
    function(vt100, elem) { return function(e) {
      if (elem == vt100.lastSelectedKey) {
        if (key == 16 /* Shift */) {
          // The user clicked the Shift key
          vt100.isShift                 = !vt100.isShift;
          vt100.showShiftState(vt100.isShift);
        } else if (key == 17 /* Ctrl */) {
          vt100.isCtrl                  = !vt100.isCtrl;
          vt100.showCtrlState(vt100.isCtrl);
        } else if (key == 18 /* Alt */) {
          vt100.isAlt                   = !vt100.isAlt;
          vt100.showAltState(vt100.isAlt);
        }
        vt100.lastSelectedKey           = undefined;
      }
      if (vt100.lastSelectedKey) {
        vt100.lastSelectedKey.className = '';
        vt100.lastSelectedKey           = undefined;
      }
      return false; }; }(this, elem) :
    // Regular keys generate key clicks, when the mouse button is released or
    // when a mouse click event is received.
    function(vt100, elem, ch, key, CH, KEY) { return function(e) {
      if (vt100.lastSelectedKey) {
        if (elem == vt100.lastSelectedKey) {
          // The user clicked a key.
          if (vt100.isShift) {
            vt100.clickedKeyboard(e, elem, CH, KEY,
                                  true, vt100.isCtrl, vt100.isAlt);
          } else {
            vt100.clickedKeyboard(e, elem, ch, key,
                                  false, vt100.isCtrl, vt100.isAlt);
          }
          vt100.isShift                 = false;
          vt100.showShiftState(false);
          vt100.isCtrl                  = false;
          vt100.showCtrlState(false);
          vt100.isAlt                   = false;
          vt100.showAltState(false);
        }
        vt100.lastSelectedKey.className = '';
        vt100.lastSelectedKey           = undefined;
      }
      elem.className                    = '';
      return false; }; }(this, elem, ch, key, CH, KEY);
  this.addListener(elem, 'mouseup', clicked);
  this.addListener(elem, 'click', clicked);

  // When moving the mouse away from a key, check if any keys need to be
  // deselected.
  this.addListener(elem, 'mouseout',
    function(vt100, elem, key) { return function(e) {
      if (key == 16 /* Shift */) {
        if (!elem.className == vt100.isShift) {
          vt100.showShiftState(vt100.isShift);
        }
      } else if (key == 17 /* Ctrl */) {
        if (!elem.className == vt100.isCtrl) {
          vt100.showCtrlState(vt100.isCtrl);
        }
      } else if (key == 18 /* Alt */) {
        if (!elem.className == vt100.isAlt) {
          vt100.showAltState(vt100.isAlt);
        }
      } else if (elem.className) {
        elem.className                  = '';
        vt100.lastSelectedKey           = elem;
      } else if (vt100.lastSelectedKey) {
        vt100.resetLastSelectedKey(e);
      }
      return false; }; }(this, elem, key));

  // When moving the mouse over a key, select it if the user is still holding
  // the mouse button down (i.e. elem == lastSelectedKey)
  this.addListener(elem, 'mouseover',
    function(vt100, elem, key) { return function(e) {
      if (elem == vt100.lastSelectedKey) {
        if (key == 16 /* Shift */) {
          if (!elem.className != vt100.isShift) {
            vt100.showShiftState(!vt100.isShift);
          }
        } else if (key == 17 /* Ctrl */) {
          if (!elem.className != vt100.isCtrl) {
            vt100.showCtrlState(!vt100.isCtrl);
          }
        } else if (key == 18 /* Alt */) {
          if (!elem.className != vt100.isAlt) {
            vt100.showAltState(!vt100.isAlt);
          }
        } else if (!elem.className) {
          elem.className                = 'selected';
        }
      } else {
        vt100.resetLastSelectedKey(e);
      }
      return false; }; }(this, elem, key));
};

VT100.prototype.initializeKeyBindings = function(elem) {
  if (elem) {
    if (elem.nodeName == "I" || elem.nodeName == "B") {
      if (elem.id) {
        // Function keys. The Javascript keycode is part of the "id"
        var i     = parseInt(elem.id);
        if (i) {
          // If the id does not parse as a number, it is not a keycode.
          this.addKeyBinding(elem, undefined, i);
        }
      } else {
        var child = elem.firstChild;
        if (child) {
          if (child.nodeName == "#text") {
            // If the key only has a text node as a child, then it is a letter.
            // Automatically compute the lower and upper case version of the
            // key.
            var text = this.getTextContent(child) ||
                       this.getTextContent(elem);
            this.addKeyBinding(elem, text.toLowerCase());
          } else if (child.nextSibling) {
            // If the key has two children, they are the lower and upper case
            // character code, respectively.
            this.addKeyBinding(elem, this.getTextContent(child), undefined,
                               this.getTextContent(child.nextSibling));
          }
        }
      }
    }
  }
  // Recursively parse all other child nodes.
  for (elem = elem.firstChild; elem; elem = elem.nextSibling) {
    this.initializeKeyBindings(elem);
  }
};

VT100.prototype.initializeKeyboardButton = function() {
  // Configure mouse event handlers for button that displays/hides keyboard
  this.addListener(this.keyboardImage, 'click',
    function(vt100) { return function(e) {
      if (vt100.keyboard.style.display != '') {
        if (vt100.reconnectBtn.style.visibility != '') {
          vt100.initializeKeyboard();
          vt100.showSoftKeyboard();
        }
      } else {
        vt100.hideSoftKeyboard();
        vt100.input.focus();
      }
      return false; }; }(this));

  // Enable button that displays keyboard
  if (this.softKeyboard) {
    this.keyboardImage.style.visibility = 'visible';
  }
};

VT100.prototype.initializeKeyboard = function() {
  // Only need to initialize the keyboard the very first time. When doing so,
  // copy the keyboard layout from the iframe.
  if (this.keyboard.firstChild) {
    return;
  }
  this.keyboard.innerHTML               =
                                    this.layout.contentDocument.body.innerHTML;
  var box                               = this.keyboard.firstChild;
  this.hideSoftKeyboard();

  // Configure mouse event handlers for on-screen keyboard
  this.addListener(this.keyboard, 'click',
    function(vt100) { return function(e) {
      vt100.hideSoftKeyboard();
      vt100.input.focus();
      return false; }; }(this));
  this.addListener(this.keyboard, 'selectstart', this.cancelEvent);
  this.addListener(box, 'click', this.cancelEvent);
  this.addListener(box, 'mouseup',
    function(vt100) { return function(e) {
      if (vt100.lastSelectedKey) {
        vt100.lastSelectedKey.className = '';
        vt100.lastSelectedKey           = undefined;
      }
      return false; }; }(this));
  this.addListener(box, 'mouseout',
    function(vt100) { return function(e) {
      return vt100.resetLastSelectedKey(e); }; }(this));
  this.addListener(box, 'mouseover',
    function(vt100) { return function(e) {
      return vt100.resetLastSelectedKey(e); }; }(this));

  // Configure SHIFT key behavior
  var style                             = document.createElement('style');
  var id                                = document.createAttribute('id');
  id.nodeValue                          = 'shift_state';
  style.setAttributeNode(id);
  var type                              = document.createAttribute('type');
  type.nodeValue                        = 'text/css';
  style.setAttributeNode(type);
  document.getElementsByTagName('head')[0].appendChild(style);

  // Set up key bindings
  this.initializeKeyBindings(box);
};

VT100.prototype.initializeElements = function(container) {
  // If the necessary objects have not already been defined in the HTML
  // page, create them now.
  if (container) {
    this.container             = container;
  } else if (!(this.container  = document.getElementById('vt100'))) {
    this.container             = document.createElement('div');
    this.container.id          = 'vt100';
    document.body.appendChild(this.container);
  }

  if (!this.getChildById(this.container, 'reconnect')   ||
      !this.getChildById(this.container, 'menu')        ||
      !this.getChildById(this.container, 'keyboard')    ||
      !this.getChildById(this.container, 'kbd_button')  ||
      !this.getChildById(this.container, 'kbd_img')     ||
      !this.getChildById(this.container, 'layout')      ||
      !this.getChildById(this.container, 'scrollable')  ||
      !this.getChildById(this.container, 'console')     ||
      !this.getChildById(this.container, 'alt_console') ||
      !this.getChildById(this.container, 'ieprobe')     ||
      !this.getChildById(this.container, 'padding')     ||
      !this.getChildById(this.container, 'cursor')      ||
      !this.getChildById(this.container, 'lineheight')  ||
      !this.getChildById(this.container, 'usercss')     ||
      !this.getChildById(this.container, 'space')       ||
      !this.getChildById(this.container, 'input')       ||
      !this.getChildById(this.container, 'cliphelper')) {
    // Only enable the "embed" object, if we have a suitable plugin. Otherwise,
    // we might get a pointless warning that a suitable plugin is not yet
    // installed. If in doubt, we'd rather just stay silent.
    var embed                  = '';
    try {
      if (typeof navigator.mimeTypes["audio/x-wav"].enabledPlugin.name !=
          'undefined') {
        embed                  = typeof suppressAllAudio != 'undefined' &&
                                 suppressAllAudio ? "" :
        '<embed classid="clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B" ' +
                       'id="beep_embed" ' +
                       'src="beep.wav" ' +
                       'autostart="false" ' +
                       'volume="100" ' +
                       'enablejavascript="true" ' +
                       'type="audio/x-wav" ' +
                       'height="16" ' +
                       'width="200" ' +
                       'style="position:absolute;left:-1000px;top:-1000px" />';
      }
    } catch (e) {
    }

    this.container.innerHTML   =
                       '<div id="reconnect" style="visibility: hidden">' +
                         '<input type="button" value="Connect" ' +
                                'onsubmit="return false" />' +
                       '</div>' +
                       '<div id="cursize" style="visibility: hidden">' +
                       '</div>' +
                       '<div id="menu"></div>' +
                       '<div id="keyboard" unselectable="on">' +
                       '</div>' +
                       '<div id="scrollable">' +
                         '<table id="kbd_button">' +
                           '<tr><td width="100%">&nbsp;</td>' +
                           '<td><img id="kbd_img" src="keyboard.png" /></td>' +
                           '<td>&nbsp;&nbsp;&nbsp;&nbsp;</td></tr>' +
                         '</table>' +
                         '<pre id="lineheight">&nbsp;</pre>' +
                         '<pre id="console">' +
                           '<pre></pre>' +
                           '<div id="ieprobe"><span>&nbsp;</span></div>' +
                         '</pre>' +
                         '<pre id="alt_console" style="display: none"></pre>' +
                         '<div id="padding"></div>' +
                         '<pre id="cursor">&nbsp;</pre>' +
                       '</div>' +
                       '<div class="hidden">' +
                         '<div id="usercss"></div>' +
                         '<pre><div><span id="space"></span></div></pre>' +
                         '<input type="textfield" id="input" />' +
                         '<input type="textfield" id="cliphelper" />' +
                         (typeof suppressAllAudio != 'undefined' &&
                          suppressAllAudio ? "" :
                         embed + '<bgsound id="beep_bgsound" loop=1 />') +
                          '<iframe id="layout" src="keyboard.html" />' +
                        '</div>';
  }

  // Find the object used for playing the "beep" sound, if any.
  if (typeof suppressAllAudio != 'undefined' && suppressAllAudio) {
    this.beeper                = undefined;
  } else {
    this.beeper                = this.getChildById(this.container,
                                                   'beep_embed');
    if (!this.beeper || !this.beeper.Play) {
      this.beeper              = this.getChildById(this.container,
                                                   'beep_bgsound');
      if (!this.beeper || typeof this.beeper.src == 'undefined') {
        this.beeper            = undefined;
      }
    }
  }

  // Initialize the variables for finding the text console and the
  // cursor.
  this.reconnectBtn            = this.getChildById(this.container,'reconnect');
  this.curSizeBox              = this.getChildById(this.container, 'cursize');
  this.menu                    = this.getChildById(this.container, 'menu');
  this.keyboard                = this.getChildById(this.container, 'keyboard');
  this.keyboardImage           = this.getChildById(this.container, 'kbd_img');
  this.layout                  = this.getChildById(this.container, 'layout');
  this.scrollable              = this.getChildById(this.container,
                                                                 'scrollable');
  this.lineheight              = this.getChildById(this.container,
                                                                 'lineheight');
  this.console                 =
                          [ this.getChildById(this.container, 'console'),
                            this.getChildById(this.container, 'alt_console') ];
  var ieProbe                  = this.getChildById(this.container, 'ieprobe');
  this.padding                 = this.getChildById(this.container, 'padding');
  this.cursor                  = this.getChildById(this.container, 'cursor');
  this.usercss                 = this.getChildById(this.container, 'usercss');
  this.space                   = this.getChildById(this.container, 'space');
  this.input                   = this.getChildById(this.container, 'input');
  this.cliphelper              = this.getChildById(this.container,
                                                                 'cliphelper');

  // Add any user selectable style sheets to the menu
  this.initializeUserCSSStyles();

  // Remember the dimensions of a standard character glyph. We would
  // expect that we could just check cursor.clientWidth/Height at any time,
  // but it turns out that browsers sometimes invalidate these values
  // (e.g. while displaying a print preview screen).
  this.cursorWidth             = this.cursor.clientWidth;
  this.cursorHeight            = this.lineheight.clientHeight;

  // IE has a slightly different boxing model, that we need to compensate for
  this.isIE                    = ieProbe.offsetTop > 1;
  ieProbe                      = undefined;
  this.console.innerHTML       = '';

  // Determine if the terminal window is positioned at the beginning of the
  // page, or if it is embedded somewhere else in the page. For full-screen
  // terminals, automatically resize whenever the browser window changes.
  var marginTop                = parseInt(this.getCurrentComputedStyle(
                                          document.body, 'marginTop'));
  var marginLeft               = parseInt(this.getCurrentComputedStyle(
                                          document.body, 'marginLeft'));
  var marginRight              = parseInt(this.getCurrentComputedStyle(
                                          document.body, 'marginRight'));
  var x                        = this.container.offsetLeft;
  var y                        = this.container.offsetTop;
  for (var parent = this.container; parent = parent.offsetParent; ) {
    x                         += parent.offsetLeft;
    y                         += parent.offsetTop;
  }
  this.isEmbedded              = marginTop != y ||
                                 marginLeft != x ||
                                 (window.innerWidth ||
                                  document.documentElement.clientWidth ||
                                  document.body.clientWidth) -
                                 marginRight != x + this.container.offsetWidth;
  if (!this.isEmbedded) {
    // Some browsers generate resize events when the terminal is first
    // shown. Disable showing the size indicator until a little bit after
    // the terminal has been rendered the first time.
    this.indicateSize          = false;
    setTimeout(function(vt100) {
      return function() {
        vt100.indicateSize     = true;
      };
    }(this), 100);
    this.addListener(window, 'resize', 
                     function(vt100) {
                       return function() {
                         vt100.hideContextMenu();
                         vt100.resizer();
                         vt100.showCurrentSize();
                        }
                      }(this));
    
    // Hide extra scrollbars attached to window
    document.body.style.margin = '0px';
    try { document.body.style.overflow ='hidden'; } catch (e) { }
    try { document.body.oncontextmenu = function() {return false;};} catch(e){}
  }

  // Set up onscreen soft keyboard
  this.initializeKeyboardButton();

  // Hide context menu
  this.hideContextMenu();

  // Add listener to reconnect button
  this.addListener(this.reconnectBtn.firstChild, 'click',
                   function(vt100) {
                     return function() {
                       var rc = vt100.reconnect();
                       vt100.input.focus();
                       return rc;
                     }
                   }(this));

  // Add input listeners
  this.addListener(this.input, 'blur',
                   function(vt100) {
                     return function() { vt100.blurCursor(); } }(this));
  this.addListener(this.input, 'focus',
                   function(vt100) {
                     return function() { vt100.focusCursor(); } }(this));
  this.addListener(this.input, 'keydown',
                   function(vt100) {
                     return function(e) {
                       if (!e) e = window.event;
                       return vt100.keyDown(e); } }(this));
  this.addListener(this.input, 'keypress',
                   function(vt100) {
                     return function(e) {
                       if (!e) e = window.event;
                       return vt100.keyPressed(e); } }(this));
  this.addListener(this.input, 'keyup',
                   function(vt100) {
                     return function(e) {
                       if (!e) e = window.event;
                       return vt100.keyUp(e); } }(this));

  // Attach listeners that move the focus to the <input> field. This way we
  // can make sure that we can receive keyboard input.
  var mouseEvent               = function(vt100, type) {
    return function(e) {
      if (!e) e = window.event;
      return vt100.mouseEvent(e, type);
    };
  };
  this.addListener(this.scrollable,'mousedown',mouseEvent(this, MOUSE_DOWN));
  this.addListener(this.scrollable,'mouseup',  mouseEvent(this, MOUSE_UP));
  this.addListener(this.scrollable,'click',    mouseEvent(this, MOUSE_CLICK));

  // Initialize the blank terminal window.
  this.currentScreen           = 0;
  this.cursorX                 = 0;
  this.cursorY                 = 0;
  this.numScrollbackLines      = 0;
  this.top                     = 0;
  this.bottom                  = 0x7FFFFFFF;
  this.scale                   = 1.0;
  this.resizer();
  this.focusCursor();
  this.input.focus();
};

VT100.prototype.getChildById = function(parent, id) {
  var nodeList = parent.all || parent.getElementsByTagName('*');
  if (typeof nodeList.namedItem == 'undefined') {
    for (var i = 0; i < nodeList.length; i++) {
      if (nodeList[i].id == id) {
        return nodeList[i];
      }
    }
    return null;
  } else {
    var elem = (parent.all || parent.getElementsByTagName('*')).namedItem(id);
    return elem ? elem[0] || elem : null;
  }
};

VT100.prototype.getCurrentComputedStyle = function(elem, style) {
  if (typeof elem.currentStyle != 'undefined') {
    return elem.currentStyle[style];
  } else {
    return document.defaultView.getComputedStyle(elem, null)[style];
  }
};

VT100.prototype.reconnect = function() {
  return false;
};

VT100.prototype.showReconnect = function(state) {
  if (state) {
    this.hideSoftKeyboard();
    this.reconnectBtn.style.visibility = '';
  } else {
    this.reconnectBtn.style.visibility = 'hidden';
  }
};

VT100.prototype.repairElements = function(console) {
  for (var line = console.firstChild; line; line = line.nextSibling) {
    if (!line.clientHeight) {
      var newLine = document.createElement(line.tagName);
      newLine.style.cssText       = line.style.cssText;
      newLine.className           = line.className;
      if (line.tagName == 'DIV') {
        for (var span = line.firstChild; span; span = span.nextSibling) {
          var newSpan             = document.createElement(span.tagName);
          newSpan.style.cssText   = span.style.cssText;
          newSpan.style.className = span.style.className;
          this.setTextContent(newSpan, this.getTextContent(span));
          newLine.appendChild(newSpan);
        }
      } else {
        this.setTextContent(newLine, this.getTextContent(line));
      }
      line.parentNode.replaceChild(newLine, line);
      line                        = newLine;
    }
  }
};

VT100.prototype.resized = function(w, h) {
};

VT100.prototype.resizer = function() {
  // Hide onscreen soft keyboard
  this.hideSoftKeyboard();

  // The cursor can get corrupted if the print-preview is displayed in Firefox.
  // Recreating it, will repair it.
  var newCursor                = document.createElement('pre');
  this.setTextContent(newCursor, ' ');
  newCursor.id                 = 'cursor';
  newCursor.style.cssText      = this.cursor.style.cssText;
  this.cursor.parentNode.insertBefore(newCursor, this.cursor);
  if (!newCursor.clientHeight) {
    // Things are broken right now. This is probably because we are
    // displaying the print-preview. Just don't change any of our settings
    // until the print dialog is closed again.
    newCursor.parentNode.removeChild(newCursor);
    return;
  } else {
    // Swap the old broken cursor for the newly created one.
    this.cursor.parentNode.removeChild(this.cursor);
    this.cursor                = newCursor;
  }

  // Really horrible things happen if the contents of the terminal changes
  // while the print-preview is showing. We get HTML elements that show up
  // in the DOM, but that do not take up any space. Find these elements and
  // try to fix them.
  this.repairElements(this.console[0]);
  this.repairElements(this.console[1]);

  // Lock the cursor size to the size of a normal character. This helps with
  // characters that are taller/shorter than normal. Unfortunately, we will
  // still get confused if somebody enters a character that is wider/narrower
  // than normal. This can happen if the browser tries to substitute a
  // characters from a different font.
  this.cursor.style.width      = this.cursorWidth  + 'px';
  this.cursor.style.height     = this.cursorHeight + 'px';

  // Adjust height for one pixel padding of the #vt100 element.
  // The latter is necessary to properly display the inactive cursor.
  var console                  = this.console[this.currentScreen];
  var height                   = (this.isEmbedded ? this.container.clientHeight
                                  : (window.innerHeight ||
                                     document.documentElement.clientHeight ||
                                     document.body.clientHeight))-1;
  var partial                  = height % this.cursorHeight;
  this.scrollable.style.height = (height > 0 ? height : 0) + 'px';
  this.padding.style.height    = (partial > 0 ? partial : 0) + 'px';
  var oldTerminalHeight        = this.terminalHeight;
  this.updateWidth();
  this.updateHeight();

  // Clip the cursor to the visible screen.
  var cx                       = this.cursorX;
  var cy                       = this.cursorY + this.numScrollbackLines;

  // The alternate screen never keeps a scroll back buffer.
  this.updateNumScrollbackLines();
  while (this.currentScreen && this.numScrollbackLines > 0) {
    console.removeChild(console.firstChild);
    this.numScrollbackLines--;
  }
  cy                          -= this.numScrollbackLines;
  if (cx < 0) {
    cx                         = 0;
  } else if (cx > this.terminalWidth) {
    cx                         = this.terminalWidth - 1;
    if (cx < 0) {
      cx                       = 0;
    }
  }
  if (cy < 0) {
    cy                         = 0;
  } else if (cy > this.terminalHeight) {
    cy                         = this.terminalHeight - 1;
    if (cy < 0) {
      cy                       = 0;
    }
  }

  // Clip the scroll region to the visible screen.
  if (this.bottom > this.terminalHeight ||
      this.bottom == oldTerminalHeight) {
    this.bottom                = this.terminalHeight;
  }
  if (this.top >= this.bottom) {
    this.top                   = this.bottom-1;
    if (this.top < 0) {
      this.top                 = 0;
    }
  }

  // Truncate lines, if necessary. Explicitly reposition cursor (this is
  // particularly important after changing the screen number), and reset
  // the scroll region to the default.
  this.truncateLines(this.terminalWidth);
  this.putString(cx, cy, '', undefined);
  this.scrollable.scrollTop    = this.numScrollbackLines *
                                 this.cursorHeight + 1;

  // Update classNames for lines in the scrollback buffer
  var line                     = console.firstChild;
  for (var i = 0; i < this.numScrollbackLines; i++) {
    line.className             = 'scrollback';
    line                       = line.nextSibling;
  }
  while (line) {
    line.className             = '';
    line                       = line.nextSibling;
  }

  // Reposition the reconnect button
  this.reconnectBtn.style.left = (this.terminalWidth*this.cursorWidth/
                                  this.scale -
                                  this.reconnectBtn.clientWidth)/2 + 'px';
  this.reconnectBtn.style.top  = (this.terminalHeight*this.cursorHeight-
                                  this.reconnectBtn.clientHeight)/2 + 'px';

  // Send notification that the window size has been changed
  this.resized(this.terminalWidth, this.terminalHeight);
};

VT100.prototype.showCurrentSize = function() {
  if (!this.indicateSize) {
    return;
  }
  this.curSizeBox.innerHTML             = '' + this.terminalWidth + 'x' +
                                               this.terminalHeight;
  this.curSizeBox.style.left            =
                                      (this.terminalWidth*this.cursorWidth/
                                       this.scale -
                                       this.curSizeBox.clientWidth)/2 + 'px';
  this.curSizeBox.style.top             =
                                      (this.terminalHeight*this.cursorHeight -
                                       this.curSizeBox.clientHeight)/2 + 'px';
  this.curSizeBox.style.visibility      = '';
  if (this.curSizeTimeout) {
    clearTimeout(this.curSizeTimeout);
  }

  // Only show the terminal size for a short amount of time after resizing.
  // Then hide this information, again. Some browsers generate resize events
  // throughout the entire resize operation. This is nice, and we will show
  // the terminal size while the user is dragging the window borders.
  // Other browsers only generate a single event when the user releases the
  // mouse. In those cases, we can only show the terminal size once at the
  // end of the resize operation.
  this.curSizeTimeout                   = setTimeout(function(vt100) {
    return function() {
      vt100.curSizeTimeout              = null;
      vt100.curSizeBox.style.visibility = 'hidden';
    };
  }(this), 1000);
};

VT100.prototype.selection = function() {
  try {
    return '' + (window.getSelection && window.getSelection() ||
                 document.selection && document.selection.type == 'Text' &&
                 document.selection.createRange().text || '');
  } catch (e) {
  }
  return '';
};

VT100.prototype.cancelEvent = function(event) {
  try {
    // For non-IE browsers
    event.stopPropagation();
    event.preventDefault();
  } catch (e) {
  }
  try {
    // For IE
    event.cancelBubble = true;
    event.returnValue  = false;
    event.button       = 0;
    event.keyCode      = 0;
  } catch (e) {
  }
  return false;
};

VT100.prototype.mousePosition = function(event) {
  var offsetX      = this.container.offsetLeft;
  var offsetY      = this.container.offsetTop;
  for (var e = this.container; e = e.offsetParent; ) {
    offsetX       += e.offsetLeft;
    offsetY       += e.offsetTop;
  }
  return [ event.clientX - offsetX,
           event.clientY - offsetY ];
};

VT100.prototype.mouseEvent = function(event, type) {
  // If any text is currently selected, do not move the focus as that would
  // invalidate the selection.
  var selection    = this.selection();
  if ((type == MOUSE_UP || type == MOUSE_CLICK) && !selection.length) {
    this.input.focus();
  }

  // Compute mouse position in characters.
  var position     = this.mousePosition(event);
  var x            = Math.floor(position[0] / this.cursorWidth);
  var y            = Math.floor((position[1] + this.scrollable.scrollTop) /
                                this.cursorHeight) - this.numScrollbackLines;
  var inside       = true;
  if (x >= this.terminalWidth) {
    x              = this.terminalWidth - 1;
    inside         = false;
  }
  if (x < 0) {
    x              = 0;
    inside         = false;
  }
  if (y >= this.terminalHeight) {
    y              = this.terminalHeight - 1;
    inside         = false;
  }
  if (y < 0) {
    y              = 0;
    inside         = false;
  }

  // Compute button number and modifier keys.
  var button       = type != MOUSE_DOWN ? 3 :
                     typeof event.pageX != 'undefined' ? event.button :
                     [ undefined, 0, 2, 0, 1, 0, 1, 0  ][event.button];
  if (button != undefined) {
    if (event.shiftKey) {
      button      |= 0x04;
    }
    if (event.altKey || event.metaKey) {
      button      |= 0x08;
    }
    if (event.ctrlKey) {
      button      |= 0x10;
    }
  }

  // Report mouse events if they happen inside of the current screen and
  // with the SHIFT key unpressed. Both of these restrictions do not apply
  // for button releases, as we always want to report those.
  if (this.mouseReporting && !selection.length &&
      (type != MOUSE_DOWN || !event.shiftKey)) {
    if (inside || type != MOUSE_DOWN) {
      if (button != undefined) {
        var report = '\u001B[M' + String.fromCharCode(button + 32) +
                                  String.fromCharCode(x      + 33) +
                                  String.fromCharCode(y      + 33);
        if (type != MOUSE_CLICK) {
          this.keysPressed(report);
        }

        // If we reported the event, stop propagating it (not sure, if this
        // actually works on most browsers; blocking the global "oncontextmenu"
        // even is still necessary).
        return this.cancelEvent(event);
      }
    }
  }

  // Bring up context menu.
  if (button == 2 && !event.shiftKey) {
    if (type == MOUSE_DOWN) {
      this.showContextMenu(position[0], position[1]);
    }
    return this.cancelEvent(event);
  }

  if (this.mouseReporting) {
    try {
      event.shiftKey         = false;
    } catch (e) {
    }
  }

  return true;
};

VT100.prototype.replaceChar = function(s, ch, repl) {
  for (var i = -1;;) {
    i = s.indexOf(ch, i + 1);
    if (i < 0) {
      break;
    }
    s = s.substr(0, i) + repl + s.substr(i + 1);
  }
  return s;
};

VT100.prototype.htmlEscape = function(s) {
  return this.replaceChar(this.replaceChar(this.replaceChar(this.replaceChar(
                s, '&', '&amp;'), '<', '&lt;'), '"', '&quot;'), ' ', '\u00A0');
};

VT100.prototype.getTextContent = function(elem) {
  return elem.textContent ||
         (typeof elem.textContent == 'undefined' ? elem.innerText : '');
};

VT100.prototype.setTextContentRaw = function(elem, s) {
  // Updating the content of an element is an expensive operation. It actually
  // pays off to first check whether the element is still unchanged.
  if (typeof elem.textContent == 'undefined') {
    if (elem.innerText != s) {
      try {
        elem.innerText = s;
      } catch (e) {
        // Very old versions of IE do not allow setting innerText. Instead,
        // remove all children, by setting innerHTML and then set the text
        // using DOM methods.
        elem.innerHTML = '';
        elem.appendChild(document.createTextNode(
                                          this.replaceChar(s, ' ', '\u00A0')));
      }
    }
  } else {
    if (elem.textContent != s) {
      elem.textContent = s;
    }
  }
};

VT100.prototype.setTextContent = function(elem, s) {
  // Check if we find any URLs in the text. If so, automatically convert them
  // to links.
  if (this.urlRE && this.urlRE.test(s)) {
    var inner          = '';
    for (;;) {
      var consumed = 0;
      if (RegExp.leftContext != null) {
        inner         += this.htmlEscape(RegExp.leftContext);
        consumed      += RegExp.leftContext.length;
      }
      var url          = this.htmlEscape(RegExp.lastMatch);
      var fullUrl      = url;

      // If no protocol was specified, try to guess a reasonable one.
      if (url.indexOf('http://') < 0 && url.indexOf('https://') < 0 &&
          url.indexOf('ftp://')  < 0 && url.indexOf('mailto:')  < 0) {
        var slash      = url.indexOf('/');
        var at         = url.indexOf('@');
        var question   = url.indexOf('?');
        if (at > 0 &&
            (at < question || question < 0) &&
            (slash < 0 || (question > 0 && slash > question))) {
          fullUrl      = 'mailto:' + url;
        } else {
          fullUrl      = (url.indexOf('ftp.') == 0 ? 'ftp://' : 'http://') +
                          url;
        }
      }

      inner           += '<a target="vt100Link" href="' + fullUrl +
                         '">' + url + '</a>';
      consumed        += RegExp.lastMatch.length;
      s                = s.substr(consumed);
      if (!this.urlRE.test(s)) {
        if (RegExp.rightContext != null) {
          inner       += this.htmlEscape(RegExp.rightContext);
        }
        break;
      }
    }
    elem.innerHTML     = inner;
    return;
  }

  this.setTextContentRaw(elem, s);
};

VT100.prototype.insertBlankLine = function(y, color, style) {
  // Insert a blank line a position y. This method ignores the scrollback
  // buffer. The caller has to add the length of the scrollback buffer to
  // the position, if necessary.
  // If the position is larger than the number of current lines, this
  // method just adds a new line right after the last existing one. It does
  // not add any missing lines in between. It is the caller's responsibility
  // to do so.
  if (!color) {
    color                = 'ansi0 bgAnsi15';
  }
  if (!style) {
    style                = '';
  }
  var line;
  if (color != 'ansi0 bgAnsi15' && !style) {
    line                 = document.createElement('pre');
    this.setTextContent(line, '\n');
  } else {
    line                 = document.createElement('div');
    var span             = document.createElement('span');
    span.style.cssText   = style;
    span.style.className = color;
    this.setTextContent(span, this.spaces(this.terminalWidth));
    line.appendChild(span);
  }
  line.style.height      = this.cursorHeight + 'px';
  var console            = this.console[this.currentScreen];
  if (console.childNodes.length > y) {
    console.insertBefore(line, console.childNodes[y]);
  } else {
    console.appendChild(line);
  }
};

VT100.prototype.updateWidth = function() {
  this.terminalWidth = Math.floor(this.console[this.currentScreen].offsetWidth/
                                  this.cursorWidth*this.scale);
  return this.terminalWidth;
};

VT100.prototype.updateHeight = function() {
  // We want to be able to display either a terminal window that fills the
  // entire browser window, or a terminal window that is contained in a
  // <div> which is embededded somewhere in the web page.
  if (this.isEmbedded) {
    // Embedded terminal. Use size of the containing <div> (id="vt100").
    this.terminalHeight = Math.floor((this.container.clientHeight-1) /
                                     this.cursorHeight);
  } else {
    // Use the full browser window.
    this.terminalHeight = Math.floor(((window.innerHeight ||
                                       document.documentElement.clientHeight ||
                                       document.body.clientHeight)-1)/
                                     this.cursorHeight);
  }
  return this.terminalHeight;
};

VT100.prototype.updateNumScrollbackLines = function() {
  var scrollback          = Math.floor(
                                this.console[this.currentScreen].offsetHeight /
                                this.cursorHeight) -
                            this.terminalHeight;
  this.numScrollbackLines = scrollback < 0 ? 0 : scrollback;
  return this.numScrollbackLines;
};

VT100.prototype.truncateLines = function(width) {
  if (width < 0) {
    width             = 0;
  }
  for (var line = this.console[this.currentScreen].firstChild; line;
       line = line.nextSibling) {
    if (line.tagName == 'DIV') {
      var x           = 0;

      // Traverse current line and truncate it once we saw "width" characters
      for (var span = line.firstChild; span;
           span = span.nextSibling) {
        var s         = this.getTextContent(span);
        var l         = s.length;
        if (x + l > width) {
          this.setTextContent(span, s.substr(0, width - x));
          while (span.nextSibling) {
            line.removeChild(line.lastChild);
          }
          break;
        }
        x            += l;
      }
      // Prune white space from the end of the current line
      var span       = line.lastChild;
      while (span &&
             span.className == 'ansi0 bgAnsi15' &&
             !span.style.cssText.length) {
        // Scan backwards looking for first non-space character
        var s         = this.getTextContent(span);
        for (var i = s.length; i--; ) {
          if (s.charAt(i) != ' ' && s.charAt(i) != '\u00A0') {
            if (i+1 != s.length) {
              this.setTextContent(s.substr(0, i+1));
            }
            span      = null;
            break;
          }
        }
        if (span) {
          var sibling = span;
          span        = span.previousSibling;
          if (span) {
            // Remove blank <span>'s from end of line
            line.removeChild(sibling);
          } else {
            // Remove entire line (i.e. <div>), if empty
            var blank = document.createElement('pre');
            blank.style.height = this.cursorHeight + 'px';
            this.setTextContent(blank, '\n');
            line.parentNode.replaceChild(blank, line);
          }
        }
      }
    }
  }
};

VT100.prototype.putString = function(x, y, text, color, style) {
  if (!color) {
    color                           = 'ansi0 bgAnsi15';
  }
  if (!style) {
    style                           = '';
  }
  var yIdx                          = y + this.numScrollbackLines;
  var line;
  var sibling;
  var s;
  var span;
  var xPos                          = 0;
  var console                       = this.console[this.currentScreen];
  if (!text.length && (yIdx >= console.childNodes.length ||
                       console.childNodes[yIdx].tagName != 'DIV')) {
    // Positioning cursor to a blank location
    span                            = null;
  } else {
    // Create missing blank lines at end of page
    while (console.childNodes.length <= yIdx) {
      // In order to simplify lookups, we want to make sure that each line
      // is represented by exactly one element (and possibly a whole bunch of
      // children).
      // For non-blank lines, we can create a <div> containing one or more
      // <span>s. For blank lines, this fails as browsers tend to optimize them
      // away. But fortunately, a <pre> tag containing a newline character
      // appears to work for all browsers (a &nbsp; would also work, but then
      // copying from the browser window would insert superfluous spaces into
      // the clipboard).
      this.insertBlankLine(yIdx);
    }
    line                            = console.childNodes[yIdx];
    
    // If necessary, promote blank '\n' line to a <div> tag
    if (line.tagName != 'DIV') {
      var div                       = document.createElement('div');
      div.style.height              = this.cursorHeight + 'px';
      div.innerHTML                 = '<span></span>';
      console.replaceChild(div, line);
      line                          = div;
    }

    // Scan through list of <span>'s until we find the one where our text
    // starts
    span                            = line.firstChild;
    var len;
    while (span.nextSibling && xPos < x) {
      len                           = this.getTextContent(span).length;
      if (xPos + len > x) {
        break;
      }
      xPos                         += len;
      span                          = span.nextSibling;
    }

    if (text.length) {
      // If current <span> is not long enough, pad with spaces or add new
      // span
      s                             = this.getTextContent(span);
      var oldColor                  = span.className;
      var oldStyle                  = span.style.cssText;
      if (xPos + s.length < x) {
        if (oldColor != 'ansi0 bgAnsi15' || oldStyle != '') {
          span                      = document.createElement('span');
          line.appendChild(span);
          span.className            = 'ansi0 bgAnsi15';
          span.style.cssText        = '';
          oldColor                  = 'ansi0 bgAnsi15';
          oldStyle                  = '';
          xPos                     += s.length;
          s                         = '';
        }
        do {
          s                        += ' ';
        } while (xPos + s.length < x);
      }
    
      // If styles do not match, create a new <span>
      var del                       = text.length - s.length + x - xPos;
      if (oldColor != color ||
          (oldStyle != style && (oldStyle || style))) {
        if (xPos == x) {
          // Replacing text at beginning of existing <span>
          if (text.length >= s.length) {
            // New text is equal or longer than existing text
            s                       = text;
          } else {
            // Insert new <span> before the current one, then remove leading
            // part of existing <span>, adjust style of new <span>, and finally
            // set its contents
            sibling                 = document.createElement('span');
            line.insertBefore(sibling, span);
            this.setTextContent(span, s.substr(text.length));
            span                    = sibling;
            s                       = text;
          }
        } else {
          // Replacing text some way into the existing <span>
          var remainder             = s.substr(x + text.length - xPos);
          this.setTextContent(span, s.substr(0, x - xPos));
          xPos                      = x;
          sibling                   = document.createElement('span');
          if (span.nextSibling) {
            line.insertBefore(sibling, span.nextSibling);
            span                    = sibling;
            if (remainder.length) {
              sibling               = document.createElement('span');
              sibling.className     = oldColor;
              sibling.style.cssText = oldStyle;
              this.setTextContent(sibling, remainder);
              line.insertBefore(sibling, span.nextSibling);
            }
          } else {
            line.appendChild(sibling);
            span                    = sibling;
            if (remainder.length) {
              sibling               = document.createElement('span');
              sibling.className     = oldColor;
              sibling.style.cssText = oldStyle;
              this.setTextContent(sibling, remainder);
              line.appendChild(sibling);
            }
          }
          s                         = text;
        }
        span.className              = color;
        span.style.cssText          = style;
      } else {
        // Overwrite (partial) <span> with new text
        s                           = s.substr(0, x - xPos) +
          text +
          s.substr(x + text.length - xPos);
      }
      this.setTextContent(span, s);

      
      // Delete all subsequent <span>'s that have just been overwritten
      sibling                       = span.nextSibling;
      while (del > 0 && sibling) {
        s                           = this.getTextContent(sibling);
        len                         = s.length;
        if (len <= del) {
          line.removeChild(sibling);
          del                      -= len;
          sibling                   = span.nextSibling;
        } else {
          this.setTextContent(sibling, s.substr(del));
          break;
        }
      }
      
      // Merge <span> with next sibling, if styles are identical
      if (sibling && span.className == sibling.className &&
          span.style.cssText == sibling.style.cssText) {
        this.setTextContent(span,
                            this.getTextContent(span) +
                            this.getTextContent(sibling));
        line.removeChild(sibling);
      }
    }
  }

  // Position cursor
  this.cursorX                      = x + text.length;
  if (this.cursorX >= this.terminalWidth) {
    this.cursorX                    = this.terminalWidth - 1;
    if (this.cursorX < 0) {
      this.cursorX                  = 0;
    }
  }
  var pixelX                        = -1;
  var pixelY                        = -1;
  if (!this.cursor.style.visibility) {
    var idx                         = this.cursorX - xPos;
    if (span) {
      // If we are in a non-empty line, take the cursor Y position from the
      // other elements in this line. If dealing with broken, non-proportional
      // fonts, this is likely to yield better results.
      pixelY                        = span.offsetTop +
                                      span.offsetParent.offsetTop;
      s                             = this.getTextContent(span);
      var nxtIdx                    = idx - s.length;
      if (nxtIdx < 0) {
        this.setTextContent(this.cursor, s.charAt(idx));
        pixelX                      = span.offsetLeft +
                                      idx*span.offsetWidth / s.length;
      } else {
        if (nxtIdx == 0) {
          pixelX                    = span.offsetLeft + span.offsetWidth;
        }
        if (span.nextSibling) {
          s                         = this.getTextContent(span.nextSibling);
          this.setTextContent(this.cursor, s.charAt(nxtIdx));
          if (pixelX < 0) {
            pixelX                  = span.nextSibling.offsetLeft +
                                      nxtIdx*span.offsetWidth / s.length;
          }
        } else {
          this.setTextContent(this.cursor, ' ');
        }
      }
    } else {
      this.setTextContent(this.cursor, ' ');
    }
  }
  if (pixelX >= 0) {
    this.cursor.style.left          = (pixelX + (this.isIE ? 1 : 0))/
                                      this.scale + 'px';
  } else {
    this.setTextContent(this.space, this.spaces(this.cursorX));
    this.cursor.style.left          = (this.space.offsetWidth +
                                       console.offsetLeft)/this.scale + 'px';
  }
  this.cursorY                      = yIdx - this.numScrollbackLines;
  if (pixelY >= 0) {
    this.cursor.style.top           = pixelY + 'px';
  } else {
    this.cursor.style.top           = yIdx*this.cursorHeight +
                                      console.offsetTop + 'px';
  }

  if (text.length) {
    // Merge <span> with previous sibling, if styles are identical
    if ((sibling = span.previousSibling) &&
        span.className == sibling.className &&
        span.style.cssText == sibling.style.cssText) {
      this.setTextContent(span,
                          this.getTextContent(sibling) +
                          this.getTextContent(span));
      line.removeChild(sibling);
    }
    
    // Prune white space from the end of the current line
    span                            = line.lastChild;
    while (span &&
           span.className == 'ansi0 bgAnsi15' &&
           !span.style.cssText.length) {
      // Scan backwards looking for first non-space character
      s                             = this.getTextContent(span);
      for (var i = s.length; i--; ) {
        if (s.charAt(i) != ' ' && s.charAt(i) != '\u00A0') {
          if (i+1 != s.length) {
            this.setTextContent(s.substr(0, i+1));
          }
          span                      = null;
          break;
        }
      }
      if (span) {
        sibling                     = span;
        span                        = span.previousSibling;
        if (span) {
          // Remove blank <span>'s from end of line
          line.removeChild(sibling);
        } else {
          // Remove entire line (i.e. <div>), if empty
          var blank                 = document.createElement('pre');
          blank.style.height        = this.cursorHeight + 'px';
          this.setTextContent(blank, '\n');
          line.parentNode.replaceChild(blank, line);
        }
      }
    }
  }
};

VT100.prototype.gotoXY = function(x, y) {
  if (x >= this.terminalWidth) {
    x           = this.terminalWidth - 1;
  }
  if (x < 0) {
    x           = 0;
  }
  var minY, maxY;
  if (this.offsetMode) {
    minY        = this.top;
    maxY        = this.bottom;
  } else {
    minY        = 0;
    maxY        = this.terminalHeight;
  }
  if (y >= maxY) {
    y           = maxY - 1;
  }
  if (y < minY) {
    y           = minY;
  }
  this.putString(x, y, '', undefined);
  this.needWrap = false;
};

VT100.prototype.gotoXaY = function(x, y) {
  this.gotoXY(x, this.offsetMode ? (this.top + y) : y);
};

VT100.prototype.refreshInvertedState = function() {
  if (this.isInverted) {
    this.scrollable.className += ' inverted';
  } else {
    this.scrollable.className = this.scrollable.className.
                                                     replace(/ *inverted/, '');
  }
};

VT100.prototype.enableAlternateScreen = function(state) {
  // Don't do anything, if we are already on the desired screen
  if ((state ? 1 : 0) == this.currentScreen) {
    // Calling the resizer is not actually necessary. But it is a good way
    // of resetting state that might have gotten corrupted.
    this.resizer();
    return;
  }
  
  // We save the full state of the normal screen, when we switch away from it.
  // But for the alternate screen, no saving is necessary. We always reset
  // it when we switch to it.
  if (state) {
    this.saveCursor();
  }

  // Display new screen, and initialize state (the resizer does that for us).
  this.currentScreen                                 = state ? 1 : 0;
  this.console[1-this.currentScreen].style.display   = 'none';
  this.console[this.currentScreen].style.display     = '';

  // Select appropriate character pitch.
  var transform                                      = this.getTransformName();
  if (transform) {
    if (state) {
      // Upon enabling the alternate screen, we switch to 80 column mode. But
      // upon returning to the regular screen, we restore the mode that was
      // in effect previously.
      this.console[1].style[transform]               = '';
    }
    var style                                        =
                             this.console[this.currentScreen].style[transform];
    this.cursor.style[transform]                     = style;
    this.space.style[transform]                      = style;
    this.scale                                       = style == '' ? 1.0:1.65;
    if (transform == 'filter') {
       this.console[this.currentScreen].style.width  = style == '' ? '165%':'';
    }
  }
  this.resizer();

  // If we switched to the alternate screen, reset it completely. Otherwise,
  // restore the saved state.
  if (state) {
    this.gotoXY(0, 0);
    this.clearRegion(0, 0, this.terminalWidth, this.terminalHeight);
  } else {
    this.restoreCursor();
  }
};

VT100.prototype.hideCursor = function() {
  var hidden = this.cursor.style.visibility == 'hidden';
  if (!hidden) {
    this.cursor.style.visibility = 'hidden';
    return true;
  }
  return false;
};

VT100.prototype.showCursor = function(x, y) {
  if (this.cursor.style.visibility) {
    this.cursor.style.visibility = '';
    this.putString(x == undefined ? this.cursorX : x,
                   y == undefined ? this.cursorY : y,
                   '', undefined);
    return true;
  }
  return false;
};

VT100.prototype.scrollBack = function() {
  var i                     = this.scrollable.scrollTop -
                              this.scrollable.clientHeight;
  this.scrollable.scrollTop = i < 0 ? 0 : i;
};

VT100.prototype.scrollFore = function() {
  var i                     = this.scrollable.scrollTop +
                              this.scrollable.clientHeight;
  this.scrollable.scrollTop = i > this.numScrollbackLines *
                                  this.cursorHeight + 1
                              ? this.numScrollbackLines *
                                this.cursorHeight + 1
                              : i;
};

VT100.prototype.spaces = function(i) {
  var s = '';
  while (i-- > 0) {
    s += ' ';
  }
  return s;
};

VT100.prototype.clearRegion = function(x, y, w, h, color, style) {
  w         += x;
  if (x < 0) {
    x        = 0;
  }
  if (w > this.terminalWidth) {
    w        = this.terminalWidth;
  }
  if ((w    -= x) <= 0) {
    return;
  }
  h         += y;
  if (y < 0) {
    y        = 0;
  }
  if (h > this.terminalHeight) {
    h        = this.terminalHeight;
  }
  if ((h    -= y) <= 0) {
    return;
  }

  // Special case the situation where we clear the entire screen, and we do
  // not have a scrollback buffer. In that case, we should just remove all
  // child nodes.
  if (!this.numScrollbackLines &&
      w == this.terminalWidth && h == this.terminalHeight &&
      (color == undefined || color == 'ansi0 bgAnsi15') && !style) {
    var console = this.console[this.currentScreen];
    while (console.lastChild) {
      console.removeChild(console.lastChild);
    }
    this.putString(this.cursorX, this.cursorY, '', undefined);
  } else {
    var hidden = this.hideCursor();
    var cx     = this.cursorX;
    var cy     = this.cursorY;
    var s      = this.spaces(w);
    for (var i = y+h; i-- > y; ) {
      this.putString(x, i, s, color, style);
    }
    hidden ? this.showCursor(cx, cy) : this.putString(cx, cy, '', undefined);
  }
};

VT100.prototype.copyLineSegment = function(dX, dY, sX, sY, w) {
  var text                            = [ ];
  var className                       = [ ];
  var style                           = [ ];
  var console                         = this.console[this.currentScreen];
  if (sY >= console.childNodes.length) {
    text[0]                           = this.spaces(w);
    className[0]                      = undefined;
    style[0]                          = undefined;
  } else {
    var line = console.childNodes[sY];
    if (line.tagName != 'DIV' || !line.childNodes.length) {
      text[0]                         = this.spaces(w);
      className[0]                    = undefined;
      style[0]                        = undefined;
    } else {
      var x                           = 0;
      for (var span = line.firstChild; span && w > 0; span = span.nextSibling){
        var s                         = this.getTextContent(span);
        var len                       = s.length;
        if (x + len > sX) {
          var o                       = sX > x ? sX - x : 0;
          text[text.length]           = s.substr(o, w);
          className[className.length] = span.className;
          style[style.length]         = span.style.cssText;
          w                          -= len - o;
        }
        x                            += len;
      }
      if (w > 0) {
        text[text.length]             = this.spaces(w);
        className[className.length]   = undefined;
        style[style.length]           = undefined;
      }
    }
  }
  var hidden                          = this.hideCursor();
  var cx                              = this.cursorX;
  var cy                              = this.cursorY;
  for (var i = 0; i < text.length; i++) {
    var color;
    if (className[i]) {
      color                           = className[i];
    } else {
      color                           = 'ansi0 bgAnsi15';
    }
    this.putString(dX, dY - this.numScrollbackLines, text[i], color, style[i]);
    dX                               += text[i].length;
  }
  hidden ? this.showCursor(cx, cy) : this.putString(cx, cy, '', undefined);
};

VT100.prototype.scrollRegion = function(x, y, w, h, incX, incY,
                                        color, style) {
  var left             = incX < 0 ? -incX : 0;
  var right            = incX > 0 ?  incX : 0;
  var up               = incY < 0 ? -incY : 0;
  var down             = incY > 0 ?  incY : 0;

  // Clip region against terminal size
  var dontScroll       = null;
  w                   += x;
  if (x < left) {
    x                  = left;
  }
  if (w > this.terminalWidth - right) {
    w                  = this.terminalWidth - right;
  }
  if ((w              -= x) <= 0) {
    dontScroll         = 1;
  }
  h                   += y;
  if (y < up) {
    y                  = up;
  }
  if (h > this.terminalHeight - down) {
    h                  = this.terminalHeight - down;
  }
  if ((h              -= y) < 0) {
    dontScroll         = 1;
  }
  if (!dontScroll) {
    if (style && style.indexOf('underline')) {
      // Different terminal emulators disagree on the attributes that
      // are used for scrolling. The consensus seems to be, never to
      // fill with underlined spaces. N.B. this is different from the
      // cases when the user blanks a region. User-initiated blanking
      // always fills with all of the current attributes.
      style            = style.replace(/text-decoration:underline;/, '');
    }

    // Compute current scroll position
    var scrollPos      = this.numScrollbackLines -
                      (this.scrollable.scrollTop-1) / this.cursorHeight;

    // Determine original cursor position. Hide cursor temporarily to avoid
    // visual artifacts.
    var hidden         = this.hideCursor();
    var cx             = this.cursorX;
    var cy             = this.cursorY;
    var console        = this.console[this.currentScreen];

    if (!incX && !x && w == this.terminalWidth) {
      // Scrolling entire lines
      if (incY < 0) {
        // Scrolling up
        if (!this.currentScreen && y == -incY &&
            h == this.terminalHeight + incY) {
          // Scrolling up with adding to the scrollback buffer. This is only
          // possible if there are at least as many lines in the console,
          // as the terminal is high
          while (console.childNodes.length < this.terminalHeight) {
            this.insertBlankLine(this.terminalHeight);
          }
          
          // Add new lines at bottom in order to force scrolling
          for (var i = 0; i < y; i++) {
            this.insertBlankLine(console.childNodes.length, color, style);
          }

          // Adjust the number of lines in the scrollback buffer by
          // removing excess entries.
          this.updateNumScrollbackLines();
          while (this.numScrollbackLines >
                 (this.currentScreen ? 0 : this.maxScrollbackLines)) {
            console.removeChild(console.firstChild);
            this.numScrollbackLines--;
          }

          // Mark lines in the scrollback buffer, so that they do not get
          // printed.
          for (var i = this.numScrollbackLines, j = -incY;
               i-- > 0 && j-- > 0; ) {
            console.childNodes[i].className = 'scrollback';
          }
        } else {
          // Scrolling up without adding to the scrollback buffer.
          for (var i = -incY;
               i-- > 0 &&
               console.childNodes.length >
               this.numScrollbackLines + y + incY; ) {
            console.removeChild(console.childNodes[
                                          this.numScrollbackLines + y + incY]);
          }

          // If we used to have a scrollback buffer, then we must make sure
          // that we add back blank lines at the bottom of the terminal.
          // Similarly, if we are scrolling in the middle of the screen,
          // we must add blank lines to ensure that the bottom of the screen
          // does not move up.
          if (this.numScrollbackLines > 0 ||
              console.childNodes.length > this.numScrollbackLines+y+h+incY) {
            for (var i = -incY; i-- > 0; ) {
              this.insertBlankLine(this.numScrollbackLines + y + h + incY,
                                   color, style);
            }
          }
        }
      } else {
        // Scrolling down
        for (var i = incY;
             i-- > 0 &&
             console.childNodes.length > this.numScrollbackLines + y + h; ) {
          console.removeChild(console.childNodes[this.numScrollbackLines+y+h]);
        }
        for (var i = incY; i--; ) {
          this.insertBlankLine(this.numScrollbackLines + y, color, style);
        }
      }
    } else {
      // Scrolling partial lines
      if (incY <= 0) {
        // Scrolling up or horizontally within a line
        for (var i = y + this.numScrollbackLines;
             i < y + this.numScrollbackLines + h;
             i++) {
          this.copyLineSegment(x + incX, i + incY, x, i, w);
        }
      } else {
        // Scrolling down
        for (var i = y + this.numScrollbackLines + h;
             i-- > y + this.numScrollbackLines; ) {
          this.copyLineSegment(x + incX, i + incY, x, i, w);
        }
      }

      // Clear blank regions
      if (incX > 0) {
        this.clearRegion(x, y, incX, h, color, style);
      } else if (incX < 0) {
        this.clearRegion(x + w + incX, y, -incX, h, color, style);
      }
      if (incY > 0) {
        this.clearRegion(x, y, w, incY, color, style);
      } else if (incY < 0) {
        this.clearRegion(x, y + h + incY, w, -incY, color, style);
      }
    }

    // Reset scroll position
    this.scrollable.scrollTop = (this.numScrollbackLines-scrollPos) *
                                this.cursorHeight + 1;

    // Move cursor back to its original position
    hidden ? this.showCursor(cx, cy) : this.putString(cx, cy, '', undefined);
  }
};

VT100.prototype.copy = function(selection) {
  if (selection == undefined) {
    selection                = this.selection();
  }
  this.internalClipboard     = undefined;
  if (selection.length) {
    try {
      // IE
      this.cliphelper.value  = selection;
      this.cliphelper.select();
      this.cliphelper.createTextRange().execCommand('copy');
    } catch (e) {
      this.internalClipboard = selection;
    }
    this.cliphelper.value    = '';
  }
};

VT100.prototype.copyLast = function() {
  // Opening the context menu can remove the selection. We try to prevent this
  // from happening, but that is not possible for all browsers. So, instead,
  // we compute the selection before showing the menu.
  this.copy(this.lastSelection);
};

VT100.prototype.pasteFnc = function() {
  var clipboard     = undefined;
  if (this.internalClipboard != undefined) {
    clipboard       = this.internalClipboard;
  } else {
    try {
      this.cliphelper.value = '';
      this.cliphelper.createTextRange().execCommand('paste');
      clipboard     = this.cliphelper.value;
    } catch (e) {
    }
  }
  this.cliphelper.value = '';
  if (clipboard && this.menu.style.visibility == 'hidden') {
    return function() {
      this.keysPressed('' + clipboard);
    };
  } else {
    return undefined;
  }
};

VT100.prototype.toggleUTF = function() {
  this.utfEnabled   = !this.utfEnabled;

  // We always persist the last value that the user selected. Not necessarily
  // the last value that a random program requested.
  this.utfPreferred = this.utfEnabled;
};

VT100.prototype.toggleBell = function() {
  this.visualBell = !this.visualBell;
};

VT100.prototype.toggleSoftKeyboard = function() {
  this.softKeyboard = !this.softKeyboard;
  this.keyboardImage.style.visibility = this.softKeyboard ? 'visible' : '';
};

VT100.prototype.deselectKeys = function(elem) {
  if (elem && elem.className == 'selected') {
    elem.className = '';
  }
  for (elem = elem.firstChild; elem; elem = elem.nextSibling) {
    this.deselectKeys(elem);
  }
};

VT100.prototype.showSoftKeyboard = function() {
  // Make sure no key is currently selected
  this.lastSelectedKey           = undefined;
  this.deselectKeys(this.keyboard);
  this.isShift                   = false;
  this.showShiftState(false);
  this.isCtrl                    = false;
  this.showCtrlState(false);
  this.isAlt                     = false;
  this.showAltState(false);

  this.keyboard.style.left       = '0px';
  this.keyboard.style.top        = '0px';
  this.keyboard.style.width      = this.container.offsetWidth  + 'px';
  this.keyboard.style.height     = this.container.offsetHeight + 'px';
  this.keyboard.style.visibility = 'hidden';
  this.keyboard.style.display    = '';

  var kbd                        = this.keyboard.firstChild;
  var scale                      = 1.0;
  var transform                  = this.getTransformName();
  if (transform) {
    kbd.style[transform]         = '';
    if (kbd.offsetWidth > 0.9 * this.container.offsetWidth) {
      scale                      = (kbd.offsetWidth/
                                    this.container.offsetWidth)/0.9;
    }
    if (kbd.offsetHeight > 0.9 * this.container.offsetHeight) {
      scale                      = Math.max((kbd.offsetHeight/
                                             this.container.offsetHeight)/0.9);
    }
    var style                    = this.getTransformStyle(transform,
                                              scale > 1.0 ? scale : undefined);
    kbd.style[transform]         = style;
  }
  if (transform == 'filter') {
    scale                        = 1.0;
  }
  kbd.style.left                 = ((this.container.offsetWidth -
                                     kbd.offsetWidth/scale)/2) + 'px';
  kbd.style.top                  = ((this.container.offsetHeight -
                                     kbd.offsetHeight/scale)/2) + 'px';

  this.keyboard.style.visibility = 'visible';
};

VT100.prototype.hideSoftKeyboard = function() {
  this.keyboard.style.display    = 'none';
};

VT100.prototype.toggleCursorBlinking = function() {
  this.blinkingCursor = !this.blinkingCursor;
};

VT100.prototype.about = function() {
  alert("VT100 Terminal Emulator " + VERSION +
        "\nCopyright 2008-2010 by Markus Gutschke\n" +
        "For more information check http://shellinabox.com");
};

VT100.prototype.hideContextMenu = function() {
  this.menu.style.visibility = 'hidden';
  this.menu.style.top        = '-100px';
  this.menu.style.left       = '-100px';
  this.menu.style.width      = '0px';
  this.menu.style.height     = '0px';
};

VT100.prototype.extendContextMenu = function(entries, actions) {
};

VT100.prototype.showContextMenu = function(x, y) {
  this.menu.innerHTML         =
    '<table class="popup" ' +
           'cellpadding="0" cellspacing="0">' +
      '<tr><td>' +
        '<ul id="menuentries">' +
          '<li id="beginclipboard">Copy</li>' +
          '<li id="endclipboard">Paste</li>' +
          '<hr />' +
          '<li id="reset">Reset</li>' +
          '<hr />' +
          '<li id="beginconfig">' +
             (this.utfEnabled ? '<img src="enabled.gif" />' : '') +
             'Unicode</li>' +
          '<li>' +
             (this.visualBell ? '<img src="enabled.gif" />' : '') +
             'Visual Bell</li>'+
          '<li>' +
             (this.softKeyboard ? '<img src="enabled.gif" />' : '') +
             'Onscreen Keyboard</li>' +
          '<li id="endconfig">' +
             (this.blinkingCursor ? '<img src="enabled.gif" />' : '') +
             'Blinking Cursor</li>'+
          (this.usercss.firstChild ?
           '<hr id="beginusercss" />' +
           this.usercss.innerHTML +
           '<hr id="endusercss" />' :
           '<hr />') +
          '<li id="about">About...</li>' +
        '</ul>' +
      '</td></tr>' +
    '</table>';

  var popup                   = this.menu.firstChild;
  var menuentries             = this.getChildById(popup, 'menuentries');

  // Determine menu entries that should be disabled
  this.lastSelection          = this.selection();
  if (!this.lastSelection.length) {
    menuentries.firstChild.className
                              = 'disabled';
  }
  var p                       = this.pasteFnc();
  if (!p) {
    menuentries.childNodes[1].className
                              = 'disabled';
  }

  // Actions for default items
  var actions                 = [ this.copyLast, p, this.reset,
                                  this.toggleUTF, this.toggleBell,
                                  this.toggleSoftKeyboard,
                                  this.toggleCursorBlinking ];

  // Actions for user CSS styles (if any)
  for (var i = 0; i < this.usercssActions.length; ++i) {
    actions[actions.length]   = this.usercssActions[i];
  }
  actions[actions.length]     = this.about;

  // Allow subclasses to dynamically add entries to the context menu
  this.extendContextMenu(menuentries, actions);

  // Hook up event listeners
  for (var node = menuentries.firstChild, i = 0; node;
       node = node.nextSibling) {
    if (node.tagName == 'LI') {
      if (node.className != 'disabled') {
        this.addListener(node, 'mouseover',
                         function(vt100, node) {
                           return function() {
                             node.className = 'hover';
                           }
                         }(this, node));
        this.addListener(node, 'mouseout',
                         function(vt100, node) {
                           return function() {
                             node.className = '';
                           }
                         }(this, node));
        this.addListener(node, 'mousedown',
                         function(vt100, action) {
                           return function(event) {
                             vt100.hideContextMenu();
                             action.call(vt100);
                             vt100.storeUserSettings();
                             return vt100.cancelEvent(event || window.event);
                           }
                         }(this, actions[i]));
        this.addListener(node, 'mouseup',
                         function(vt100) {
                           return function(event) {
                             return vt100.cancelEvent(event || window.event);
                           }
                         }(this));
        this.addListener(node, 'mouseclick',
                         function(vt100) {
                           return function(event) {
                             return vt100.cancelEvent(event || window.event);
                           }
                         }());
      }
      i++;
    }
  }

  // Position menu next to the mouse pointer
  this.menu.style.left        = '0px';
  this.menu.style.top         = '0px';
  this.menu.style.width       =  this.container.offsetWidth  + 'px';
  this.menu.style.height      =  this.container.offsetHeight + 'px';
  popup.style.left            = '0px';
  popup.style.top             = '0px';
  
  var margin                  = 2;
  if (x + popup.clientWidth >= this.container.offsetWidth - margin) {
    x              = this.container.offsetWidth-popup.clientWidth - margin - 1;
  }
  if (x < margin) {
    x                         = margin;
  }
  if (y + popup.clientHeight >= this.container.offsetHeight - margin) {
    y            = this.container.offsetHeight-popup.clientHeight - margin - 1;
  }
  if (y < margin) {
    y                         = margin;
  }
  popup.style.left            = x + 'px';
  popup.style.top             = y + 'px';

  // Block all other interactions with the terminal emulator
  this.addListener(this.menu, 'click', function(vt100) {
                                         return function() {
                                           vt100.hideContextMenu();
                                         }
                                       }(this));

  // Show the menu
  this.menu.style.visibility  = '';
};

VT100.prototype.keysPressed = function(ch) {
  for (var i = 0; i < ch.length; i++) {
    var c = ch.charCodeAt(i);
    this.vt100(c >= 7 && c <= 15 ||
               c == 24 || c == 26 || c == 27 || c >= 32
               ? String.fromCharCode(c) : '<' + c + '>');
  }
};

VT100.prototype.applyModifiers = function(ch, event) {
  if (ch) {
    if (event.ctrlKey) {
      if (ch >= 32 && ch <= 127) {
        // For historic reasons, some control characters are treated specially
        switch (ch) {
        case /* 3 */ 51: ch  =  27; break;
        case /* 4 */ 52: ch  =  28; break;
        case /* 5 */ 53: ch  =  29; break;
        case /* 6 */ 54: ch  =  30; break;
        case /* 7 */ 55: ch  =  31; break;
        case /* 8 */ 56: ch  = 127; break;
        case /* ? */ 63: ch  = 127; break;
        default:         ch &=  31; break;
        }
      }
    }
    return String.fromCharCode(ch);
  } else {
    return undefined;
  }
};

VT100.prototype.handleKey = function(event) {
  // this.vt100('H: c=' + event.charCode + ', k=' + event.keyCode +
  //            (event.shiftKey || event.ctrlKey || event.altKey ||
  //             event.metaKey ? ', ' +
  //             (event.shiftKey ? 'S' : '') + (event.ctrlKey ? 'C' : '') +
  //             (event.altKey ? 'A' : '') + (event.metaKey ? 'M' : '') : '') +
  //            '\r\n');
  var ch, key;
  if (typeof event.charCode != 'undefined') {
    // non-IE keypress events have a translated charCode value. Also, our
    // fake events generated when receiving keydown events include this data
    // on all browsers.
    ch                                = event.charCode;
    key                               = event.keyCode;
  } else {
    // When sending a keypress event, IE includes the translated character
    // code in the keyCode field.
    ch                                = event.keyCode;
    key                               = undefined;
  }

  // Apply modifier keys (ctrl and shift)
  if (ch) {
    key                               = undefined;
  }
  ch                                  = this.applyModifiers(ch, event);

  // By this point, "ch" is either defined and contains the character code, or
  // it is undefined and "key" defines the code of a function key 
  if (ch != undefined) {
    this.scrollable.scrollTop         = this.numScrollbackLines *
                                        this.cursorHeight + 1;
  } else {
    if ((event.altKey || event.metaKey) && !event.shiftKey && !event.ctrlKey) {
      // Many programs have difficulties dealing with parametrized escape
      // sequences for function keys. Thus, if ALT is the only modifier
      // key, return Emacs-style keycodes for commonly used keys.
      switch (key) {
      case  33: /* Page Up      */ ch = '\u001B<';                      break;
      case  34: /* Page Down    */ ch = '\u001B>';                      break;
      case  37: /* Left         */ ch = '\u001Bb';                      break;
      case  38: /* Up           */ ch = '\u001Bp';                      break;
      case  39: /* Right        */ ch = '\u001Bf';                      break;
      case  40: /* Down         */ ch = '\u001Bn';                      break;
      case  46: /* Delete       */ ch = '\u001Bd';                      break;
      default:                                                          break;
      }
    } else if (event.shiftKey && !event.ctrlKey &&
               !event.altKey && !event.metaKey) {
      switch (key) {
      case  33: /* Page Up      */ this.scrollBack();                   return;
      case  34: /* Page Down    */ this.scrollFore();                   return;
      default:                                                          break;
      }
    }
    if (ch == undefined) {
      switch (key) {
      case   8: /* Backspace    */ ch = '\u007f';                       break;
      case   9: /* Tab          */ ch = '\u0009';                       break;
      case  10: /* Return       */ ch = '\u000A';                       break;
      case  13: /* Enter        */ ch = this.crLfMode ?
                                        '\r\n' : '\r';                  break;
      case  16: /* Shift        */                                      return;
      case  17: /* Ctrl         */                                      return;
      case  18: /* Alt          */                                      return;
      case  19: /* Break        */                                      return;
      case  20: /* Caps Lock    */                                      return;
      case  27: /* Escape       */ ch = '\u001B';                       break;
      case  33: /* Page Up      */ ch = '\u001B[5~';                    break;
      case  34: /* Page Down    */ ch = '\u001B[6~';                    break;
      case  35: /* End          */ ch = '\u001BOF';                     break;
      case  36: /* Home         */ ch = '\u001BOH';                     break;
      case  37: /* Left         */ ch = this.cursorKeyMode ?
                             '\u001BOD' : '\u001B[D';                   break;
      case  38: /* Up           */ ch = this.cursorKeyMode ?
                             '\u001BOA' : '\u001B[A';                   break;
      case  39: /* Right        */ ch = this.cursorKeyMode ?
                             '\u001BOC' : '\u001B[C';                   break;
      case  40: /* Down         */ ch = this.cursorKeyMode ?
                             '\u001BOB' : '\u001B[B';                   break;
      case  45: /* Insert       */ ch = '\u001B[2~';                    break;
      case  46: /* Delete       */ ch = '\u001B[3~';                    break;
      case  91: /* Left Window  */                                      return;
      case  92: /* Right Window */                                      return;
      case  93: /* Select       */                                      return;
      case  96: /* 0            */ ch = this.applyModifiers(48, event); break;
      case  97: /* 1            */ ch = this.applyModifiers(49, event); break;
      case  98: /* 2            */ ch = this.applyModifiers(50, event); break;
      case  99: /* 3            */ ch = this.applyModifiers(51, event); break;
      case 100: /* 4            */ ch = this.applyModifiers(52, event); break;
      case 101: /* 5            */ ch = this.applyModifiers(53, event); break;
      case 102: /* 6            */ ch = this.applyModifiers(54, event); break;
      case 103: /* 7            */ ch = this.applyModifiers(55, event); break;
      case 104: /* 8            */ ch = this.applyModifiers(56, event); break;
      case 105: /* 9            */ ch = this.applyModifiers(58, event); break;
      case 106: /* *            */ ch = this.applyModifiers(42, event); break;
      case 107: /* +            */ ch = this.applyModifiers(43, event); break;
      case 109: /* -            */ ch = this.applyModifiers(45, event); break;
      case 110: /* .            */ ch = this.applyModifiers(46, event); break;
      case 111: /* /            */ ch = this.applyModifiers(47, event); break;
      case 112: /* F1           */ ch = '\u001BOP';                     break;
      case 113: /* F2           */ ch = '\u001BOQ';                     break;
      case 114: /* F3           */ ch = '\u001BOR';                     break;
      case 115: /* F4           */ ch = '\u001BOS';                     break;
      case 116: /* F5           */ ch = '\u001B[15~';                   break;
      case 117: /* F6           */ ch = '\u001B[17~';                   break;
      case 118: /* F7           */ ch = '\u001B[18~';                   break;
      case 119: /* F8           */ ch = '\u001B[19~';                   break;
      case 120: /* F9           */ ch = '\u001B[20~';                   break;
      case 121: /* F10          */ ch = '\u001B[21~';                   break;
      case 122: /* F11          */ ch = '\u001B[23~';                   break;
      case 123: /* F12          */ ch = '\u001B[24~';                   break;
      case 144: /* Num Lock     */                                      return;
      case 145: /* Scroll Lock  */                                      return;
      case 186: /* ;            */ ch = this.applyModifiers(59, event); break;
      case 187: /* =            */ ch = this.applyModifiers(61, event); break;
      case 188: /* ,            */ ch = this.applyModifiers(44, event); break;
      case 189: /* -            */ ch = this.applyModifiers(45, event); break;
      case 190: /* .            */ ch = this.applyModifiers(46, event); break;
      case 191: /* /            */ ch = this.applyModifiers(47, event); break;
      case 192: /* `            */ ch = this.applyModifiers(96, event); break;
      case 219: /* [            */ ch = this.applyModifiers(91, event); break;
      case 220: /* \            */ ch = this.applyModifiers(92, event); break;
      case 221: /* ]            */ ch = this.applyModifiers(93, event); break;
      case 222: /* '            */ ch = this.applyModifiers(39, event); break;
      default:                                                          return;
      }
      this.scrollable.scrollTop       = this.numScrollbackLines *
                                        this.cursorHeight + 1;
    }
  }

  // "ch" now contains the sequence of keycodes to send. But we might still
  // have to apply the effects of modifier keys.
  if (event.shiftKey || event.ctrlKey || event.altKey || event.metaKey) {
    var start, digit, part1, part2;
    if ((start = ch.substr(0, 2)) == '\u001B[') {
      for (part1 = start;
           part1.length < ch.length &&
             (digit = ch.charCodeAt(part1.length)) >= 48 && digit <= 57; ) {
        part1                         = ch.substr(0, part1.length + 1);
      }
      part2                           = ch.substr(part1.length);
      if (part1.length > 2) {
        part1                        += ';';
      }
    } else if (start == '\u001BO') {
      part1                           = start;
      part2                           = ch.substr(2);
    }
    if (part1 != undefined) {
      ch                              = part1                                 +
                                       ((event.shiftKey             ? 1 : 0)  +
                                        (event.altKey|event.metaKey ? 2 : 0)  +
                                        (event.ctrlKey              ? 4 : 0)) +
                                        part2;
    } else if (ch.length == 1 && (event.altKey || event.metaKey)) {
      ch                              = '\u001B' + ch;
    }
  }

  if (this.menu.style.visibility == 'hidden') {
    // this.vt100('R: c=');
    // for (var i = 0; i < ch.length; i++)
    //   this.vt100((i != 0 ? ', ' : '') + ch.charCodeAt(i));
    // this.vt100('\r\n');
    this.keysPressed(ch);
  }
};

VT100.prototype.inspect = function(o, d) {
  if (d == undefined) {
    d       = 0;
  }
  var rc    = '';
  if (typeof o == 'object' && ++d < 2) {
    rc      = '[\r\n';
    for (i in o) {
      rc   += this.spaces(d * 2) + i + ' -> ';
      try {
        rc += this.inspect(o[i], d);
      } catch (e) {
        rc += '?' + '?' + '?\r\n';
      }
    }
    rc     += ']\r\n';
  } else {
    rc     += ('' + o).replace(/\n/g, ' ').replace(/ +/g,' ') + '\r\n';
  }
  return rc;
};

VT100.prototype.checkComposedKeys = function(event) {
  // Composed keys (at least on Linux) do not generate normal events.
  // Instead, they get entered into the text field. We normally catch
  // this on the next keyup event.
  var s              = this.input.value;
  if (s.length) {
    this.input.value = '';
    if (this.menu.style.visibility == 'hidden') {
      this.keysPressed(s);
    }
  }
};

VT100.prototype.fixEvent = function(event) {
  // Some browsers report AltGR as a combination of ALT and CTRL. As AltGr
  // is used as a second-level selector, clear the modifier bits before
  // handling the event.
  if (event.ctrlKey && event.altKey) {
    var fake                = [ ];
    fake.charCode           = event.charCode;
    fake.keyCode            = event.keyCode;
    fake.ctrlKey            = false;
    fake.shiftKey           = event.shiftKey;
    fake.altKey             = false;
    fake.metaKey            = event.metaKey;
    return fake;
  }

  // Some browsers fail to translate keys, if both shift and alt/meta is
  // pressed at the same time. We try to translate those cases, but that
  // only works for US keyboard layouts.
  if (event.shiftKey) {
    var u                   = undefined;
    var s                   = undefined;
    switch (this.lastNormalKeyDownEvent.keyCode) {
    case  39: /* ' -> " */ u = 39; s =  34; break;
    case  44: /* , -> < */ u = 44; s =  60; break;
    case  45: /* - -> _ */ u = 45; s =  95; break;
    case  46: /* . -> > */ u = 46; s =  62; break;
    case  47: /* / -> ? */ u = 47; s =  63; break;

    case  48: /* 0 -> ) */ u = 48; s =  41; break;
    case  49: /* 1 -> ! */ u = 49; s =  33; break;
    case  50: /* 2 -> @ */ u = 50; s =  64; break;
    case  51: /* 3 -> # */ u = 51; s =  35; break;
    case  52: /* 4 -> $ */ u = 52; s =  36; break;
    case  53: /* 5 -> % */ u = 53; s =  37; break;
    case  54: /* 6 -> ^ */ u = 54; s =  94; break;
    case  55: /* 7 -> & */ u = 55; s =  38; break;
    case  56: /* 8 -> * */ u = 56; s =  42; break;
    case  57: /* 9 -> ( */ u = 57; s =  40; break;

    case  59: /* ; -> : */ u = 59; s =  58; break;
    case  61: /* = -> + */ u = 61; s =  43; break;
    case  91: /* [ -> { */ u = 91; s = 123; break;
    case  92: /* \ -> | */ u = 92; s = 124; break;
    case  93: /* ] -> } */ u = 93; s = 125; break; 
    case  96: /* ` -> ~ */ u = 96; s = 126; break;

    case 109: /* - -> _ */ u = 45; s =  95; break;
    case 111: /* / -> ? */ u = 47; s =  63; break;

    case 186: /* ; -> : */ u = 59; s =  58; break;
    case 187: /* = -> + */ u = 61; s =  43; break;
    case 188: /* , -> < */ u = 44; s =  60; break;
    case 189: /* - -> _ */ u = 45; s =  95; break;
    case 190: /* . -> > */ u = 46; s =  62; break;
    case 191: /* / -> ? */ u = 47; s =  63; break;
    case 192: /* ` -> ~ */ u = 96; s = 126; break;
    case 219: /* [ -> { */ u = 91; s = 123; break;
    case 220: /* \ -> | */ u = 92; s = 124; break;
    case 221: /* ] -> } */ u = 93; s = 125; break; 
    case 222: /* ' -> " */ u = 39; s =  34; break;
    default:                                break;
    }
    if (s && (event.charCode == u || event.charCode == 0)) {
      var fake              = [ ];
      fake.charCode         = s;
      fake.keyCode          = event.keyCode;
      fake.ctrlKey          = event.ctrlKey;
      fake.shiftKey         = event.shiftKey;
      fake.altKey           = event.altKey;
      fake.metaKey          = event.metaKey;
      return fake;
    }
  }
  return event;
};

VT100.prototype.keyDown = function(event) {
  // this.vt100('D: c=' + event.charCode + ', k=' + event.keyCode +
  //            (event.shiftKey || event.ctrlKey || event.altKey ||
  //             event.metaKey ? ', ' +
  //             (event.shiftKey ? 'S' : '') + (event.ctrlKey ? 'C' : '') +
  //             (event.altKey ? 'A' : '') + (event.metaKey ? 'M' : '') : '') +
  //            '\r\n');
  this.checkComposedKeys(event);
  this.lastKeyPressedEvent      = undefined;
  this.lastKeyDownEvent         = undefined;
  this.lastNormalKeyDownEvent   = event;

  var asciiKey                  =
    event.keyCode ==  32                         ||
    event.keyCode >=  48 && event.keyCode <=  57 ||
    event.keyCode >=  65 && event.keyCode <=  90;
  var alphNumKey                =
    asciiKey                                     ||
    event.keyCode >=  96 && event.keyCode <= 105 ||
    event.keyCode == 226;
  var normalKey                 =
    alphNumKey                                   ||
    event.keyCode ==  59 || event.keyCode ==  61 ||
    event.keyCode == 106 || event.keyCode == 107 ||
    event.keyCode >= 109 && event.keyCode <= 111 ||
    event.keyCode >= 186 && event.keyCode <= 192 ||
    event.keyCode >= 219 && event.keyCode <= 223 ||
    event.keyCode == 252;
  try {
    if (navigator.appName == 'Konqueror') {
      normalKey                |= event.keyCode < 128;
    }
  } catch (e) {
  }

  // We normally prefer to look at keypress events, as they perform the
  // translation from keyCode to charCode. This is important, as the
  // translation is locale-dependent.
  // But for some keys, we must intercept them during the keydown event,
  // as they would otherwise get interpreted by the browser.
  // Even, when doing all of this, there are some keys that we can never
  // intercept. This applies to some of the menu navigation keys in IE.
  // In fact, we see them, but we cannot stop IE from seeing them, too.
  if ((event.charCode || event.keyCode) &&
      ((alphNumKey && (event.ctrlKey || event.altKey || event.metaKey) &&
        !event.shiftKey &&
        // Some browsers signal AltGR as both CTRL and ALT. Do not try to
        // interpret this sequence ourselves, as some keyboard layouts use
        // it for second-level layouts.
        !(event.ctrlKey && event.altKey)) ||
       this.catchModifiersEarly && normalKey && !alphNumKey &&
       (event.ctrlKey || event.altKey || event.metaKey) ||
       !normalKey)) {
    this.lastKeyDownEvent       = event;
    var fake                    = [ ];
    fake.ctrlKey                = event.ctrlKey;
    fake.shiftKey               = event.shiftKey;
    fake.altKey                 = event.altKey;
    fake.metaKey                = event.metaKey;
    if (asciiKey) {
      fake.charCode             = event.keyCode;
      fake.keyCode              = 0;
    } else {
      fake.charCode             = 0;
      fake.keyCode              = event.keyCode;
      if (!alphNumKey && event.shiftKey) {
        fake                    = this.fixEvent(fake);
      }
    }

    this.handleKey(fake);
    this.lastNormalKeyDownEvent = undefined;

    try {
      // For non-IE browsers
      event.stopPropagation();
      event.preventDefault();
    } catch (e) {
    }
    try {
      // For IE
      event.cancelBubble = true;
      event.returnValue  = false;
      event.keyCode      = 0;
    } catch (e) {
    }

    return false;
  }
  return true;
};

VT100.prototype.keyPressed = function(event) {
  // this.vt100('P: c=' + event.charCode + ', k=' + event.keyCode +
  //            (event.shiftKey || event.ctrlKey || event.altKey ||
  //             event.metaKey ? ', ' +
  //             (event.shiftKey ? 'S' : '') + (event.ctrlKey ? 'C' : '') +
  //             (event.altKey ? 'A' : '') + (event.metaKey ? 'M' : '') : '') +
  //            '\r\n');
  if (this.lastKeyDownEvent) {
    // If we already processed the key on keydown, do not process it
    // again here. Ideally, the browser should not even have generated a
    // keypress event in this case. But that does not appear to always work.
    this.lastKeyDownEvent     = undefined;
  } else {
    this.handleKey(event.altKey || event.metaKey
                   ? this.fixEvent(event) : event);
  }

  try {
    // For non-IE browsers
    event.preventDefault();
  } catch (e) {
  }

  try {
    // For IE
    event.cancelBubble = true;
    event.returnValue  = false;
    event.keyCode      = 0;
  } catch (e) {
  }

  this.lastNormalKeyDownEvent = undefined;
  this.lastKeyPressedEvent    = event;
  return false;
};

VT100.prototype.keyUp = function(event) {
  // this.vt100('U: c=' + event.charCode + ', k=' + event.keyCode +
  //            (event.shiftKey || event.ctrlKey || event.altKey ||
  //             event.metaKey ? ', ' +
  //             (event.shiftKey ? 'S' : '') + (event.ctrlKey ? 'C' : '') +
  //             (event.altKey ? 'A' : '') + (event.metaKey ? 'M' : '') : '') +
  //            '\r\n');
  if (this.lastKeyPressedEvent) {
    // The compose key on Linux occasionally confuses the browser and keeps
    // inserting bogus characters into the input field, even if just a regular
    // key has been pressed. Detect this case and drop the bogus characters.
    (event.target ||
     event.srcElement).value      = '';
  } else {
    // This is usually were we notice that a key has been composed and
    // thus failed to generate normal events.
    this.checkComposedKeys(event);

    // Some browsers don't report keypress events if ctrl or alt is pressed
    // for non-alphanumerical keys. Patch things up for now, but in the
    // future we will catch these keys earlier (in the keydown handler).
    if (this.lastNormalKeyDownEvent) {
      // this.vt100('ENABLING EARLY CATCHING OF MODIFIER KEYS\r\n');
      this.catchModifiersEarly    = true;
      var asciiKey                =
        event.keyCode ==  32                         ||
        event.keyCode >=  48 && event.keyCode <=  57 ||
        event.keyCode >=  65 && event.keyCode <=  90;
      var alphNumKey              =
        asciiKey                                     ||
        event.keyCode >=  96 && event.keyCode <= 105;
      var normalKey               =
        alphNumKey                                   ||
        event.keyCode ==  59 || event.keyCode ==  61 ||
        event.keyCode == 106 || event.keyCode == 107 ||
        event.keyCode >= 109 && event.keyCode <= 111 ||
        event.keyCode >= 186 && event.keyCode <= 192 ||
        event.keyCode >= 219 && event.keyCode <= 223 ||
        event.keyCode == 252;
      var fake                    = [ ];
      fake.ctrlKey                = event.ctrlKey;
      fake.shiftKey               = event.shiftKey;
      fake.altKey                 = event.altKey;
      fake.metaKey                = event.metaKey;
      if (asciiKey) {
        fake.charCode             = event.keyCode;
        fake.keyCode              = 0;
      } else {
        fake.charCode             = 0;
        fake.keyCode              = event.keyCode;
        if (!alphNumKey && (event.ctrlKey || event.altKey || event.metaKey)) {
          fake                    = this.fixEvent(fake);
        }
      }
      this.lastNormalKeyDownEvent = undefined;
      this.handleKey(fake);
    }
  }

  try {
    // For IE
    event.cancelBubble            = true;
    event.returnValue             = false;
    event.keyCode                 = 0;
  } catch (e) {
  }

  this.lastKeyDownEvent           = undefined;
  this.lastKeyPressedEvent        = undefined;
  return false;
};

VT100.prototype.animateCursor = function(inactive) {
  if (!this.cursorInterval) {
    this.cursorInterval       = setInterval(
      function(vt100) {
        return function() {
          vt100.animateCursor();

          // Use this opportunity to check whether the user entered a composed
          // key, or whether somebody pasted text into the textfield.
          vt100.checkComposedKeys();
        }
      }(this), 500);
  }
  if (inactive != undefined || this.cursor.className != 'inactive') {
    if (inactive) {
      this.cursor.className   = 'inactive';
    } else {
      if (this.blinkingCursor) {
        this.cursor.className = this.cursor.className == 'bright'
                                ? 'dim' : 'bright';
      } else {
        this.cursor.className = 'bright';
      }
    }
  }
};

VT100.prototype.blurCursor = function() {
  this.animateCursor(true);
};

VT100.prototype.focusCursor = function() {
  this.animateCursor(false);
};

VT100.prototype.flashScreen = function() {
  this.isInverted       = !this.isInverted;
  this.refreshInvertedState();
  this.isInverted       = !this.isInverted;
  setTimeout(function(vt100) {
               return function() {
                 vt100.refreshInvertedState();
               };
             }(this), 100);
};

VT100.prototype.beep = function() {
  if (this.visualBell) {
    this.flashScreen();
  } else {
    try {
      this.beeper.Play();
    } catch (e) {
      try {
        this.beeper.src = 'beep.wav';
      } catch (e) {
      }
    }
  }
};

VT100.prototype.bs = function() {
  if (this.cursorX > 0) {
    this.gotoXY(this.cursorX - 1, this.cursorY);
    this.needWrap = false;
  }
};

VT100.prototype.ht = function(count) {
  if (count == undefined) {
    count        = 1;
  }
  var cx         = this.cursorX;
  while (count-- > 0) {
    while (cx++ < this.terminalWidth) {
      var tabState = this.userTabStop[cx];
      if (tabState == false) {
        // Explicitly cleared tab stop
        continue;
      } else if (tabState) {
        // Explicitly set tab stop
        break;
      } else {
        // Default tab stop at each eighth column
        if (cx % 8 == 0) {
          break;
        }
      }
    }
  }
  if (cx > this.terminalWidth - 1) {
    cx           = this.terminalWidth - 1;
  }
  if (cx != this.cursorX) {
    this.gotoXY(cx, this.cursorY);
  }
};

VT100.prototype.rt = function(count) {
  if (count == undefined) {
    count          = 1 ;
  }
  var cx           = this.cursorX;
  while (count-- > 0) {
    while (cx-- > 0) {
      var tabState = this.userTabStop[cx];
      if (tabState == false) {
        // Explicitly cleared tab stop
        continue;
      } else if (tabState) {
        // Explicitly set tab stop
        break;
      } else {
        // Default tab stop at each eighth column
        if (cx % 8 == 0) {
          break;
        }
      }
    }
  }
  if (cx < 0) {
    cx             = 0;
  }
  if (cx != this.cursorX) {
    this.gotoXY(cx, this.cursorY);
  }
};

VT100.prototype.cr = function() {
  this.gotoXY(0, this.cursorY);
  this.needWrap = false;
};

VT100.prototype.lf = function(count) {
  if (count == undefined) {
    count    = 1;
  } else {
    if (count > this.terminalHeight) {
      count  = this.terminalHeight;
    }
    if (count < 1) {
      count  = 1;
    }
  }
  while (count-- > 0) {
    if (this.cursorY == this.bottom - 1) {
      this.scrollRegion(0, this.top + 1,
                        this.terminalWidth, this.bottom - this.top - 1,
                        0, -1, this.color, this.style);
      offset = undefined;
    } else if (this.cursorY < this.terminalHeight - 1) {
      this.gotoXY(this.cursorX, this.cursorY + 1);
    }
  }
};

VT100.prototype.ri = function(count) {
  if (count == undefined) {
    count   = 1;
  } else {
    if (count > this.terminalHeight) {
      count = this.terminalHeight;
    }
    if (count < 1) {
      count = 1;
    }
  }
  while (count-- > 0) {
    if (this.cursorY == this.top) {
      this.scrollRegion(0, this.top,
                        this.terminalWidth, this.bottom - this.top - 1,
                        0, 1, this.color, this.style);
    } else if (this.cursorY > 0) {
      this.gotoXY(this.cursorX, this.cursorY - 1);
    }
  }
  this.needWrap = false;
};

VT100.prototype.respondID = function() {
  this.respondString += '\u001B[?6c';
};

VT100.prototype.respondSecondaryDA = function() {
  this.respondString += '\u001B[>0;0;0c';
};


VT100.prototype.updateStyle = function() {
  this.style   = '';
  if (this.attr & ATTR_UNDERLINE) {
    this.style = 'text-decoration:underline;';
  }
  var bg       = (this.attr >> 4) & 0xF;
  var fg       =  this.attr       & 0xF;
  if (this.attr & ATTR_REVERSE) {
    var tmp    = bg;
    bg         = fg;
    fg         = tmp;
  }
  if ((this.attr & (ATTR_REVERSE | ATTR_DIM)) == ATTR_DIM) {
    fg         = 8; // Dark grey
  } else if (this.attr & ATTR_BRIGHT) {
    fg        |= 8;
  }
  if (this.attr & ATTR_BLINK) {
    bg        ^= 8;
  }
  // Make some readability enhancements. Most notably, disallow identical
  // background and foreground colors.
  if (bg == fg) {
    if ((fg   ^= 8) == 7) {
      fg       = 8;
    }
  }
  // And disallow bright colors on a light-grey background.
  if (bg == 7 && fg >= 8) {
    if ((fg   -= 8) == 7) {
      fg       = 8;
    }
  }

  this.color   = 'ansi' + fg + ' bgAnsi' + bg;
};

VT100.prototype.setAttrColors = function(attr) {
  if (attr != this.attr) {
    this.attr = attr;
    this.updateStyle();
  }
};

VT100.prototype.saveCursor = function() {
  this.savedX[this.currentScreen]     = this.cursorX;
  this.savedY[this.currentScreen]     = this.cursorY;
  this.savedAttr[this.currentScreen]  = this.attr;
  this.savedUseGMap                   = this.useGMap;
  for (var i = 0; i < 4; i++) {
    this.savedGMap[i]                 = this.GMap[i];
  }
  this.savedValid[this.currentScreen] = true;
};

VT100.prototype.restoreCursor = function() {
  if (!this.savedValid[this.currentScreen]) {
    return;
  }
  this.attr      = this.savedAttr[this.currentScreen];
  this.updateStyle();
  this.useGMap   = this.savedUseGMap;
  for (var i = 0; i < 4; i++) {
    this.GMap[i] = this.savedGMap[i];
  }
  this.translate = this.GMap[this.useGMap];
  this.needWrap  = false;
  this.gotoXY(this.savedX[this.currentScreen],
              this.savedY[this.currentScreen]);
};

VT100.prototype.getTransformName = function() {
  var styles = [ 'transform', 'WebkitTransform', 'MozTransform', 'filter' ];
  for (var i = 0; i < styles.length; ++i) {
    if (typeof this.console[0].style[styles[i]] != 'undefined') {
      return styles[i];
    }
  }
  return undefined;
};

VT100.prototype.getTransformStyle = function(transform, scale) {
  return scale && scale != 1.0
    ? transform == 'filter'
      ? 'progid:DXImageTransform.Microsoft.Matrix(' +
                                 'M11=' + (1.0/scale) + ',M12=0,M21=0,M22=1,' +
                                 "sizingMethod='auto expand')"
      : 'translateX(-50%) ' +
        'scaleX(' + (1.0/scale) + ') ' +
        'translateX(50%)'
    : '';
};

VT100.prototype.set80_132Mode = function(state) {
  var transform                  = this.getTransformName();
  if (transform) {
    if ((this.console[this.currentScreen].style[transform] != '') == state) {
      return;
    }
    var style                    = state ?
                                   this.getTransformStyle(transform, 1.65):'';
    this.console[this.currentScreen].style[transform] = style;
    this.cursor.style[transform] = style;
    this.space.style[transform]  = style;
    this.scale                   = state ? 1.65 : 1.0;
    if (transform == 'filter') {
      this.console[this.currentScreen].style.width = state ? '165%' : '';
    }
    this.resizer();
  }
};

VT100.prototype.setMode = function(state) {
  for (var i = 0; i <= this.npar; i++) {
    if (this.isQuestionMark) {
      switch (this.par[i]) {
      case  1: this.cursorKeyMode      = state;                      break;
      case  3: this.set80_132Mode(state);                            break;
      case  5: this.isInverted = state; this.refreshInvertedState(); break;
      case  6: this.offsetMode         = state;                      break;
      case  7: this.autoWrapMode       = state;                      break;
      case 1000:
      case  9: this.mouseReporting     = state;                      break;
      case 25: this.cursorNeedsShowing = state;
               if (state) { this.showCursor(); }
               else       { this.hideCursor(); }                     break;
      case 1047:
      case 1049:
      case 47: this.enableAlternateScreen(state);                    break;
      default:                                                       break;
      }
    } else {
      switch (this.par[i]) {
      case  3: this.dispCtrl           = state;                      break;
      case  4: this.insertMode         = state;                      break;
      case  20:this.crLfMode           = state;                      break;
      default:                                                       break;
      }
    }
  }
};

VT100.prototype.statusReport = function() {
  // Ready and operational.
  this.respondString += '\u001B[0n';
};

VT100.prototype.cursorReport = function() {
  this.respondString += '\u001B[' +
                        (this.cursorY + (this.offsetMode ? this.top + 1 : 1)) +
                        ';' +
                        (this.cursorX + 1) +
                        'R';
};

VT100.prototype.setCursorAttr = function(setAttr, xorAttr) {
  // Changing of cursor color is not implemented.
};

VT100.prototype.openPrinterWindow = function() {
  var rc            = true;
  try {
    if (!this.printWin || this.printWin.closed) {
      this.printWin = window.open('', 'print-output',
        'width=800,height=600,directories=no,location=no,menubar=yes,' +
        'status=no,toolbar=no,titlebar=yes,scrollbars=yes,resizable=yes');
      this.printWin.document.body.innerHTML =
        '<link rel="stylesheet" href="' +
          document.location.protocol + '//' + document.location.host +
          document.location.pathname.replace(/[^/]*$/, '') +
          'print-styles.css" type="text/css">\n' +
        '<div id="options"><input id="autoprint" type="checkbox"' +
          (this.autoprint ? ' checked' : '') + '>' +
          'Automatically, print page(s) when job is ready' +
        '</input></div>\n' +
        '<div id="spacer"><input type="checkbox">&nbsp;</input></div>' +
        '<pre id="print"></pre>\n';
      var autoprint = this.printWin.document.getElementById('autoprint');
      this.addListener(autoprint, 'click',
                       (function(vt100, autoprint) {
                         return function() {
                           vt100.autoprint = autoprint.checked;
                           vt100.storeUserSettings();
                           return false;
                         };
                       })(this, autoprint));
      this.printWin.document.title = 'ShellInABox Printer Output';
    }
  } catch (e) {
    // Maybe, a popup blocker prevented us from working. Better catch the
    // exception, so that we won't break the entire terminal session. The
    // user probably needs to disable the blocker first before retrying the
    // operation.
    rc              = false;
  }
  rc               &= this.printWin && !this.printWin.closed &&
                      (this.printWin.innerWidth ||
                       this.printWin.document.documentElement.clientWidth ||
                       this.printWin.document.body.clientWidth) > 1;

  if (!rc && this.printing == 100) {
    // Different popup blockers work differently. We try to detect a couple
    // of common methods. And then we retry again a brief amount later, as
    // false positives are otherwise possible. If we are sure that there is
    // a popup blocker in effect, we alert the user to it. This is helpful
    // as some popup blockers have minimal or no UI, and the user might not
    // notice that they are missing the popup. In any case, we only show at
    // most one message per print job.
    this.printing   = true;
    setTimeout((function(win) {
                  return function() {
                    if (!win || win.closed ||
                        (win.innerWidth ||
                         win.document.documentElement.clientWidth ||
                         win.document.body.clientWidth) <= 1) {
                      alert('Attempted to print, but a popup blocker ' +
                            'prevented the printer window from opening');
                    }
                  };
                })(this.printWin), 2000);
  }
  return rc;
};

VT100.prototype.sendToPrinter = function(s) {
  this.openPrinterWindow();
  try {
    var doc   = this.printWin.document;
    var print = doc.getElementById('print');
    if (print.lastChild && print.lastChild.nodeName == '#text') {
      print.lastChild.textContent += this.replaceChar(s, ' ', '\u00A0');
    } else {
      print.appendChild(doc.createTextNode(this.replaceChar(s, ' ','\u00A0')));
    }
  } catch (e) {
    // There probably was a more aggressive popup blocker that prevented us
    // from accessing the printer windows.
  }
};

VT100.prototype.sendControlToPrinter = function(ch) {
  // We get called whenever doControl() is active. But for the printer, we
  // only implement a basic line printer that doesn't understand most of
  // the escape sequences of the VT100 terminal. In fact, the only escape
  // sequence that we really need to recognize is '^[[5i' for turning the
  // printer off.
  try {
    switch (ch) {
    case  9:
      // HT
      this.openPrinterWindow();
      var doc                 = this.printWin.document;
      var print               = doc.getElementById('print');
      var chars               = print.lastChild &&
                                print.lastChild.nodeName == '#text' ?
                                print.lastChild.textContent.length : 0;
      this.sendToPrinter(this.spaces(8 - (chars % 8)));
      break;
    case 10:
      // CR
      break;
    case 12:
      // FF
      this.openPrinterWindow();
      var pageBreak           = this.printWin.document.createElement('div');
      pageBreak.className     = 'pagebreak';
      pageBreak.innerHTML     = '<hr />';
      this.printWin.document.getElementById('print').appendChild(pageBreak);
      break;
    case 13:
      // LF
      this.openPrinterWindow();
      var lineBreak           = this.printWin.document.createElement('br');
      this.printWin.document.getElementById('print').appendChild(lineBreak);
      break;
    case 27:
      // ESC
      this.isEsc              = ESesc;
      break;
    default:
      switch (this.isEsc) {
      case ESesc:
        this.isEsc            = ESnormal;
        switch (ch) {
        case 0x5B /*[*/:
          this.isEsc          = ESsquare;
          break;
        default:
          break;
        }
        break;
      case ESsquare:
        this.npar             = 0;
        this.par              = [ 0, 0, 0, 0, 0, 0, 0, 0,
                                  0, 0, 0, 0, 0, 0, 0, 0 ];
        this.isEsc            = ESgetpars;
        this.isQuestionMark   = ch == 0x3F /*?*/;
        if (this.isQuestionMark) {
          break;
        }
        // Fall through
      case ESgetpars: 
        if (ch == 0x3B /*;*/) {
          this.npar++;
          break;
        } else if (ch >= 0x30 /*0*/ && ch <= 0x39 /*9*/) {
          var par             = this.par[this.npar];
          if (par == undefined) {
            par               = 0;
          }
          this.par[this.npar] = 10*par + (ch & 0xF);
          break;
        } else {
          this.isEsc          = ESgotpars;
        }
        // Fall through
      case ESgotpars:
        this.isEsc            = ESnormal;
        if (this.isQuestionMark) {
          break;
        }
        switch (ch) {
        case 0x69 /*i*/:
          this.csii(this.par[0]);
          break;
        default:
          break;
        }
        break;
      default:
        this.isEsc            = ESnormal;
        break;
      }
      break;
    }
  } catch (e) {
    // There probably was a more aggressive popup blocker that prevented us
    // from accessing the printer windows.
  }
};

VT100.prototype.csiAt = function(number) {
  // Insert spaces
  if (number == 0) {
    number      = 1;
  }
  if (number > this.terminalWidth - this.cursorX) {
    number      = this.terminalWidth - this.cursorX;
  }
  this.scrollRegion(this.cursorX, this.cursorY,
                    this.terminalWidth - this.cursorX - number, 1,
                    number, 0, this.color, this.style);
  this.needWrap = false;
};

VT100.prototype.csii = function(number) {
  // Printer control
  switch (number) {
  case 0: // Print Screen
    window.print();
    break;
  case 4: // Stop printing
    try {
      if (this.printing && this.printWin && !this.printWin.closed) {
        var print = this.printWin.document.getElementById('print');
        while (print.lastChild &&
               print.lastChild.tagName == 'DIV' &&
               print.lastChild.className == 'pagebreak') {
          // Remove trailing blank pages
          print.removeChild(print.lastChild);
        }
        if (this.autoprint) {
          this.printWin.print();
        }
      }
    } catch (e) {
    }
    this.printing = false;
    break;
  case 5: // Start printing
    if (!this.printing && this.printWin && !this.printWin.closed) {
      this.printWin.document.getElementById('print').innerHTML = '';
    }
    this.printing = 100;
    break;
  default:
    break;
  }
};

VT100.prototype.csiJ = function(number) {
  switch (number) {
  case 0: // Erase from cursor to end of display
    this.clearRegion(this.cursorX, this.cursorY,
                     this.terminalWidth - this.cursorX, 1,
                     this.color, this.style);
    if (this.cursorY < this.terminalHeight-2) {
      this.clearRegion(0, this.cursorY+1,
                       this.terminalWidth, this.terminalHeight-this.cursorY-1,
                       this.color, this.style);
    }
    break;
  case 1: // Erase from start to cursor
    if (this.cursorY > 0) {
      this.clearRegion(0, 0,
                       this.terminalWidth, this.cursorY,
                       this.color, this.style);
    }
    this.clearRegion(0, this.cursorY, this.cursorX + 1, 1,
                     this.color, this.style);
    break;
  case 2: // Erase whole display
    this.clearRegion(0, 0, this.terminalWidth, this.terminalHeight,
                     this.color, this.style);
    break;
  default:
    return;
  }
  needWrap = false;
};

VT100.prototype.csiK = function(number) {
  switch (number) {
  case 0: // Erase from cursor to end of line
    this.clearRegion(this.cursorX, this.cursorY,
                     this.terminalWidth - this.cursorX, 1,
                     this.color, this.style);
    break;
  case 1: // Erase from start of line to cursor
    this.clearRegion(0, this.cursorY, this.cursorX + 1, 1,
                     this.color, this.style);
    break;
  case 2: // Erase whole line
    this.clearRegion(0, this.cursorY, this.terminalWidth, 1,
                     this.color, this.style);
    break;
  default:
    return;
  }
  needWrap = false;
};

VT100.prototype.csiL = function(number) {
  // Open line by inserting blank line(s)
  if (this.cursorY >= this.bottom) {
    return;
  }
  if (number == 0) {
    number = 1;
  }
  if (number > this.bottom - this.cursorY) {
    number = this.bottom - this.cursorY;
  }
  this.scrollRegion(0, this.cursorY,
                    this.terminalWidth, this.bottom - this.cursorY - number,
                    0, number, this.color, this.style);
  needWrap = false;
};

VT100.prototype.csiM = function(number) {
  // Delete line(s), scrolling up the bottom of the screen.
  if (this.cursorY >= this.bottom) {
    return;
  }
  if (number == 0) {
    number = 1;
  }
  if (number > this.bottom - this.cursorY) {
    number = bottom - cursorY;
  }
  this.scrollRegion(0, this.cursorY + number,
                    this.terminalWidth, this.bottom - this.cursorY - number,
                    0, -number, this.color, this.style);
  needWrap = false;
};

VT100.prototype.csim = function() {
  for (var i = 0; i <= this.npar; i++) {
    switch (this.par[i]) {
    case 0:  this.attr  = ATTR_DEFAULT;                                break;
    case 1:  this.attr  = (this.attr & ~ATTR_DIM)|ATTR_BRIGHT;         break;
    case 2:  this.attr  = (this.attr & ~ATTR_BRIGHT)|ATTR_DIM;         break;
    case 4:  this.attr |= ATTR_UNDERLINE;                              break;
    case 5:  this.attr |= ATTR_BLINK;                                  break;
    case 7:  this.attr |= ATTR_REVERSE;                                break;
    case 10:
      this.translate    = this.GMap[this.useGMap];
      this.dispCtrl     = false;
      this.toggleMeta   = false;
      break;
    case 11:
      this.translate    = this.CodePage437Map;
      this.dispCtrl     = true;
      this.toggleMeta   = false;
      break;
    case 12:
      this.translate    = this.CodePage437Map;
      this.dispCtrl     = true;
      this.toggleMeta   = true;
      break;
    case 21:
    case 22: this.attr &= ~(ATTR_BRIGHT|ATTR_DIM);                     break;
    case 24: this.attr &= ~ ATTR_UNDERLINE;                            break;
    case 25: this.attr &= ~ ATTR_BLINK;                                break;
    case 27: this.attr &= ~ ATTR_REVERSE;                              break;
    case 38: this.attr  = (this.attr & ~(ATTR_DIM|ATTR_BRIGHT|0x0F))|
                          ATTR_UNDERLINE;                              break;
    case 39: this.attr &= ~(ATTR_DIM|ATTR_BRIGHT|ATTR_UNDERLINE|0x0F); break;
    case 49: this.attr |= 0xF0;                                        break;
    default:
      if (this.par[i] >= 30 && this.par[i] <= 37) {
          var fg        = this.par[i] - 30;
          this.attr     = (this.attr & ~0x0F) | fg;
      } else if (this.par[i] >= 40 && this.par[i] <= 47) {
          var bg        = this.par[i] - 40;
          this.attr     = (this.attr & ~0xF0) | (bg << 4);
      }
      break;
    }
  }
  this.updateStyle();
};

VT100.prototype.csiP = function(number) {
  // Delete character(s) following cursor
  if (number == 0) {
    number = 1;
  }
  if (number > this.terminalWidth - this.cursorX) {
    number = this.terminalWidth - this.cursorX;
  }
  this.scrollRegion(this.cursorX + number, this.cursorY,
                    this.terminalWidth - this.cursorX - number, 1,
                    -number, 0, this.color, this.style);
  needWrap = false;
};

VT100.prototype.csiX = function(number) {
  // Clear characters following cursor
  if (number == 0) {
    number++;
  }
  if (number > this.terminalWidth - this.cursorX) {
    number = this.terminalWidth - this.cursorX;
  }
  this.clearRegion(this.cursorX, this.cursorY, number, 1,
                   this.color, this.style);
  needWrap = false;
};

VT100.prototype.settermCommand = function() {
  // Setterm commands are not implemented
};

VT100.prototype.doControl = function(ch) {
  if (this.printing) {
    this.sendControlToPrinter(ch);
    return '';
  }
  var lineBuf                = '';
  switch (ch) {
  case 0x00: /* ignored */                                              break;
  case 0x08: this.bs();                                                 break;
  case 0x09: this.ht();                                                 break;
  case 0x0A:
  case 0x0B:
  case 0x0C:
  case 0x84: this.lf(); if (!this.crLfMode)                             break;
  case 0x0D: this.cr();                                                 break;
  case 0x85: this.cr(); this.lf();                                      break;
  case 0x0E: this.useGMap     = 1;
             this.translate   = this.GMap[1];
             this.dispCtrl    = true;                                   break;
  case 0x0F: this.useGMap     = 0;
             this.translate   = this.GMap[0];
             this.dispCtrl    = false;                                  break;
  case 0x18:
  case 0x1A: this.isEsc       = ESnormal;                               break;
  case 0x1B: this.isEsc       = ESesc;                                  break;
  case 0x7F: /* ignored */                                              break;
  case 0x88: this.userTabStop[this.cursorX] = true;                     break;
  case 0x8D: this.ri();                                                 break;
  case 0x8E: this.isEsc       = ESss2;                                  break;
  case 0x8F: this.isEsc       = ESss3;                                  break;
  case 0x9A: this.respondID();                                          break;
  case 0x9B: this.isEsc       = ESsquare;                               break;
  case 0x07: if (this.isEsc != ESstatus) {
               this.beep();                                             break;
             }
             /* fall thru */
  default:   switch (this.isEsc) {
    case ESesc:
      this.isEsc              = ESnormal;
      switch (ch) {
/*%*/ case 0x25: this.isEsc   = ESpercent;                              break;
/*(*/ case 0x28: this.isEsc   = ESsetG0;                                break;
/*-*/ case 0x2D:
/*)*/ case 0x29: this.isEsc   = ESsetG1;                                break;
/*.*/ case 0x2E:
/***/ case 0x2A: this.isEsc   = ESsetG2;                                break;
/*/*/ case 0x2F:
/*+*/ case 0x2B: this.isEsc   = ESsetG3;                                break;
/*#*/ case 0x23: this.isEsc   = EShash;                                 break;
/*7*/ case 0x37: this.saveCursor();                                     break;
/*8*/ case 0x38: this.restoreCursor();                                  break;
/*>*/ case 0x3E: this.applKeyMode = false;                              break;
/*=*/ case 0x3D: this.applKeyMode = true;                               break;
/*D*/ case 0x44: this.lf();                                             break;
/*E*/ case 0x45: this.cr(); this.lf();                                  break;
/*M*/ case 0x4D: this.ri();                                             break;
/*N*/ case 0x4E: this.isEsc   = ESss2;                                  break;
/*O*/ case 0x4F: this.isEsc   = ESss3;                                  break;
/*H*/ case 0x48: this.userTabStop[this.cursorX] = true;                 break;
/*Z*/ case 0x5A: this.respondID();                                      break;
/*[*/ case 0x5B: this.isEsc   = ESsquare;                               break;
/*]*/ case 0x5D: this.isEsc   = ESnonstd;                               break;
/*c*/ case 0x63: this.reset();                                          break;
/*g*/ case 0x67: this.flashScreen();                                    break;
      default:                                                          break;
      }
      break;
    case ESnonstd:
      switch (ch) {
/*0*/ case 0x30:
/*1*/ case 0x31:
/*2*/ case 0x32: this.statusString = ''; this.isEsc  = ESstatus;        break;
/*P*/ case 0x50: this.npar    = 0; this.par = [ 0, 0, 0, 0, 0, 0, 0 ];
                 this.isEsc   = ESpalette;                              break;
/*R*/ case 0x52: // Palette support is not implemented
                 this.isEsc   = ESnormal;                               break;
      default:   this.isEsc   = ESnormal;                               break;
      }
      break;
    case ESpalette:
      if ((ch >= 0x30 /*0*/ && ch <= 0x39 /*9*/) ||
          (ch >= 0x41 /*A*/ && ch <= 0x46 /*F*/) ||
          (ch >= 0x61 /*a*/ && ch <= 0x66 /*f*/)) {
        this.par[this.npar++] = ch > 0x39  /*9*/ ? (ch & 0xDF) - 55
                                                : (ch & 0xF);
        if (this.npar == 7) {
          // Palette support is not implemented
          this.isEsc          = ESnormal;
        }
      } else {
        this.isEsc            = ESnormal;
      }
      break;
    case ESsquare:
      this.npar               = 0;
      this.par                = [ 0, 0, 0, 0, 0, 0, 0, 0,
                                  0, 0, 0, 0, 0, 0, 0, 0 ];
      this.isEsc              = ESgetpars;
/*[*/ if (ch == 0x5B) { // Function key
        this.isEsc            = ESfunckey;
        break;
      } else {
/*?*/   this.isQuestionMark   = ch == 0x3F;
        if (this.isQuestionMark) {
          break;
        }
      }
      // Fall through
    case ESdeviceattr:
    case ESgetpars: 
/*;*/ if (ch == 0x3B) {
        this.npar++;
        break;
      } else if (ch >= 0x30 /*0*/ && ch <= 0x39 /*9*/) {
        var par               = this.par[this.npar];
        if (par == undefined) {
          par                 = 0;
        }
        this.par[this.npar]   = 10*par + (ch & 0xF);
        break;
      } else if (this.isEsc == ESdeviceattr) {
        switch (ch) {
/*c*/   case 0x63: if (this.par[0] == 0) this.respondSecondaryDA();     break;
/*m*/   case 0x6D: /* (re)set key modifier resource values */           break;
/*n*/   case 0x6E: /* disable key modifier resource values */           break;
/*p*/   case 0x70: /* set pointer mode resource value */                break;
        default:                                                        break;
        }
        this.isEsc            = ESnormal;
        break;
      } else {
        this.isEsc            = ESgotpars;
      }
      // Fall through
    case ESgotpars:
      this.isEsc              = ESnormal;
      if (this.isQuestionMark) {
        switch (ch) {
/*h*/   case 0x68: this.setMode(true);                                  break;
/*l*/   case 0x6C: this.setMode(false);                                 break;
/*c*/   case 0x63: this.setCursorAttr(this.par[2], this.par[1]);        break;
        default:                                                        break;
        }
        this.isQuestionMark   = false;
        break;
      }
      switch (ch) {
/*!*/ case 0x21: this.isEsc   = ESbang;                                 break;
/*>*/ case 0x3E: if (!this.npar) this.isEsc  = ESdeviceattr;            break;
/*G*/ case 0x47:
/*`*/ case 0x60: this.gotoXY(this.par[0] - 1, this.cursorY);            break;
/*A*/ case 0x41: this.gotoXY(this.cursorX,
                             this.cursorY - (this.par[0] ? this.par[0] : 1));
                                                                        break;
/*B*/ case 0x42:
/*e*/ case 0x65: this.gotoXY(this.cursorX,
                             this.cursorY + (this.par[0] ? this.par[0] : 1));
                                                                        break;
/*C*/ case 0x43:
/*a*/ case 0x61: this.gotoXY(this.cursorX + (this.par[0] ? this.par[0] : 1),
                             this.cursorY);                             break;
/*D*/ case 0x44: this.gotoXY(this.cursorX - (this.par[0] ? this.par[0] : 1),
                             this.cursorY);                             break;
/*E*/ case 0x45: this.gotoXY(0, this.cursorY + (this.par[0] ? this.par[0] :1));
                                                                        break;
/*F*/ case 0x46: this.gotoXY(0, this.cursorY - (this.par[0] ? this.par[0] :1));
                                                                        break;
/*d*/ case 0x64: this.gotoXaY(this.cursorX, this.par[0] - 1);           break;
/*H*/ case 0x48:
/*f*/ case 0x66: this.gotoXaY(this.par[1] - 1, this.par[0] - 1);        break;
/*I*/ case 0x49: this.ht(this.par[0] ? this.par[0] : 1);                break;
/*@*/ case 0x40: this.csiAt(this.par[0]);                               break;
/*i*/ case 0x69: this.csii(this.par[0]);                                break;
/*J*/ case 0x4A: this.csiJ(this.par[0]);                                break;
/*K*/ case 0x4B: this.csiK(this.par[0]);                                break;
/*L*/ case 0x4C: this.csiL(this.par[0]);                                break;
/*M*/ case 0x4D: this.csiM(this.par[0]);                                break;
/*m*/ case 0x6D: this.csim();                                           break;
/*P*/ case 0x50: this.csiP(this.par[0]);                                break;
/*X*/ case 0x58: this.csiX(this.par[0]);                                break;
/*S*/ case 0x53: this.lf(this.par[0] ? this.par[0] : 1);                break;
/*T*/ case 0x54: this.ri(this.par[0] ? this.par[0] : 1);                break;
/*c*/ case 0x63: if (!this.par[0]) this.respondID();                    break;
/*g*/ case 0x67: if (this.par[0] == 0) {
                   this.userTabStop[this.cursorX] = false;
                 } else if (this.par[0] == 2 || this.par[0] == 3) {
                   this.userTabStop               = [ ];
                   for (var i = 0; i < this.terminalWidth; i++) {
                     this.userTabStop[i]          = false;
                   }
                 }
                 break;
/*h*/ case 0x68: this.setMode(true);                                    break;
/*l*/ case 0x6C: this.setMode(false);                                   break;
/*n*/ case 0x6E: switch (this.par[0]) {
                 case 5: this.statusReport();                           break;
                 case 6: this.cursorReport();                           break;
                 default:                                               break;
                 }
                 break;
/*q*/ case 0x71: // LED control not implemented
                                                                        break;
/*r*/ case 0x72: var t        = this.par[0] ? this.par[0] : 1;
                 var b        = this.par[1] ? this.par[1]
                                            : this.terminalHeight;
                 if (t < b && b <= this.terminalHeight) {
                   this.top   = t - 1;
                   this.bottom= b;
                   this.gotoXaY(0, 0);
                 }
                 break;
/*b*/ case 0x62: var c        = this.par[0] ? this.par[0] : 1;
                 if (c > this.terminalWidth * this.terminalHeight) {
                   c          = this.terminalWidth * this.terminalHeight;
                 }
                 while (c-- > 0) {
                   lineBuf   += this.lastCharacter;
                 }
                 break;
/*s*/ case 0x73: this.saveCursor();                                     break;
/*u*/ case 0x75: this.restoreCursor();                                  break;
/*Z*/ case 0x5A: this.rt(this.par[0] ? this.par[0] : 1);                break;
/*]*/ case 0x5D: this.settermCommand();                                 break;
      default:                                                          break;
      }
      break;
    case ESbang:
      if (ch == 'p') {
        this.reset();
      }
      this.isEsc              = ESnormal;
      break;
    case ESpercent:
      this.isEsc              = ESnormal;
      switch (ch) {
/*@*/ case 0x40: this.utfEnabled = false;                               break;
/*G*/ case 0x47:
/*8*/ case 0x38: this.utfEnabled = true;                                break;
      default:                                                          break;
      }
      break;
    case ESfunckey:
      this.isEsc              = ESnormal;                               break;
    case EShash:
      this.isEsc              = ESnormal;
/*8*/ if (ch == 0x38) {
        // Screen alignment test not implemented
      }
      break;
    case ESsetG0:
    case ESsetG1:
    case ESsetG2:
    case ESsetG3:
      var g                   = this.isEsc - ESsetG0;
      this.isEsc              = ESnormal;
      switch (ch) {
/*0*/ case 0x30: this.GMap[g] = this.VT100GraphicsMap;                  break;
/*A*/ case 0x42:
/*B*/ case 0x42: this.GMap[g] = this.Latin1Map;                         break;
/*U*/ case 0x55: this.GMap[g] = this.CodePage437Map;                    break;
/*K*/ case 0x4B: this.GMap[g] = this.DirectToFontMap;                   break;
      default:                                                          break;
      }
      if (this.useGMap == g) {
        this.translate        = this.GMap[g];
      }
      break;
    case ESstatus:
      if (ch == 0x07) {
        if (this.statusString && this.statusString.charAt(0) == ';') {
          this.statusString   = this.statusString.substr(1);
        }
        try {
          window.status       = this.statusString;
        } catch (e) {
        }
        this.isEsc            = ESnormal;
      } else {
        this.statusString    += String.fromCharCode(ch);
      }
      break;
    case ESss2:
    case ESss3:
      if (ch < 256) {
          ch                  = this.GMap[this.isEsc - ESss2 + 2]
                                         [this.toggleMeta ? (ch | 0x80) : ch];
        if ((ch & 0xFF00) == 0xF000) {
          ch                  = ch & 0xFF;
        } else if (ch == 0xFEFF || (ch >= 0x200A && ch <= 0x200F)) {
          this.isEsc         = ESnormal;                                break;
        }
      }
      this.lastCharacter      = String.fromCharCode(ch);
      lineBuf                += this.lastCharacter;
      this.isEsc              = ESnormal;                               break;
    default:
      this.isEsc              = ESnormal;                               break;
    }
    break;
  }
  return lineBuf;
};

VT100.prototype.renderString = function(s, showCursor) {
  if (this.printing) {
    this.sendToPrinter(s);
    if (showCursor) {
      this.showCursor();
    }
    return;
  }

  // We try to minimize the number of DOM operations by coalescing individual
  // characters into strings. This is a significant performance improvement.
  var incX = s.length;
  if (incX > this.terminalWidth - this.cursorX) {
    incX   = this.terminalWidth - this.cursorX;
    if (incX <= 0) {
      return;
    }
    s      = s.substr(0, incX - 1) + s.charAt(s.length - 1);
  }
  if (showCursor) {
    // Minimize the number of calls to putString(), by avoiding a direct
    // call to this.showCursor()
    this.cursor.style.visibility = '';
  }
  this.putString(this.cursorX, this.cursorY, s, this.color, this.style);
};

VT100.prototype.vt100 = function(s) {
  this.cursorNeedsShowing = this.hideCursor();
  this.respondString      = '';
  var lineBuf             = '';
  for (var i = 0; i < s.length; i++) {
    var ch = s.charCodeAt(i);
    if (this.utfEnabled) {
      // Decode UTF8 encoded character
      if (ch > 0x7F) {
        if (this.utfCount > 0 && (ch & 0xC0) == 0x80) {
          this.utfChar    = (this.utfChar << 6) | (ch & 0x3F);
          if (--this.utfCount <= 0) {
            if (this.utfChar > 0xFFFF || this.utfChar < 0) {
              ch = 0xFFFD;
            } else {
              ch          = this.utfChar;
            }
          } else {
            continue;
          }
        } else {
          if ((ch & 0xE0) == 0xC0) {
            this.utfCount = 1;
            this.utfChar  = ch & 0x1F;
          } else if ((ch & 0xF0) == 0xE0) {
            this.utfCount = 2;
            this.utfChar  = ch & 0x0F;
          } else if ((ch & 0xF8) == 0xF0) {
            this.utfCount = 3;
            this.utfChar  = ch & 0x07;
          } else if ((ch & 0xFC) == 0xF8) {
            this.utfCount = 4;
            this.utfChar  = ch & 0x03;
          } else if ((ch & 0xFE) == 0xFC) {
            this.utfCount = 5;
            this.utfChar  = ch & 0x01;
          } else {
            this.utfCount = 0;
          }
          continue;
        }
      } else {
        this.utfCount     = 0;
      }
    }
    var isNormalCharacter =
      (ch >= 32 && ch <= 127 || ch >= 160 ||
       this.utfEnabled && ch >= 128 ||
       !(this.dispCtrl ? this.ctrlAlways : this.ctrlAction)[ch & 0x1F]) &&
      (ch != 0x7F || this.dispCtrl);
    
    if (isNormalCharacter && this.isEsc == ESnormal) {
      if (ch < 256) {
        ch                = this.translate[this.toggleMeta ? (ch | 0x80) : ch];
      }
      if ((ch & 0xFF00) == 0xF000) {
        ch                = ch & 0xFF;
      } else if (ch == 0xFEFF || (ch >= 0x200A && ch <= 0x200F)) {
        continue;
      }
      if (!this.printing) {
        if (this.needWrap || this.insertMode) {
          if (lineBuf) {
            this.renderString(lineBuf);
            lineBuf       = '';
          }
        }
        if (this.needWrap) {
          this.cr(); this.lf();
        }
        if (this.insertMode) {
          this.scrollRegion(this.cursorX, this.cursorY,
                            this.terminalWidth - this.cursorX - 1, 1,
                            1, 0, this.color, this.style);
        }
      }
      this.lastCharacter  = String.fromCharCode(ch);
      lineBuf            += this.lastCharacter;
      if (!this.printing &&
          this.cursorX + lineBuf.length >= this.terminalWidth) {
        this.needWrap     = this.autoWrapMode;
      }
    } else {
      if (lineBuf) {
        this.renderString(lineBuf);
        lineBuf           = '';
      }
      var expand          = this.doControl(ch);
      if (expand.length) {
        var r             = this.respondString;
        this.respondString= r + this.vt100(expand);
      }
    }
  }
  if (lineBuf) {
    this.renderString(lineBuf, this.cursorNeedsShowing);
  } else if (this.cursorNeedsShowing) {
    this.showCursor();
  }
  return this.respondString;
};

VT100.prototype.Latin1Map = [
0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007,
0x0008, 0x0009, 0x000A, 0x000B, 0x000C, 0x000D, 0x000E, 0x000F,
0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017,
0x0018, 0x0019, 0x001A, 0x001B, 0x001C, 0x001D, 0x001E, 0x001F,
0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027,
0x0028, 0x0029, 0x002A, 0x002B, 0x002C, 0x002D, 0x002E, 0x002F,
0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037,
0x0038, 0x0039, 0x003A, 0x003B, 0x003C, 0x003D, 0x003E, 0x003F,
0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
0x0048, 0x0049, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F,
0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
0x0058, 0x0059, 0x005A, 0x005B, 0x005C, 0x005D, 0x005E, 0x005F,
0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067,
0x0068, 0x0069, 0x006A, 0x006B, 0x006C, 0x006D, 0x006E, 0x006F,
0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077,
0x0078, 0x0079, 0x007A, 0x007B, 0x007C, 0x007D, 0x007E, 0x007F,
0x0080, 0x0081, 0x0082, 0x0083, 0x0084, 0x0085, 0x0086, 0x0087,
0x0088, 0x0089, 0x008A, 0x008B, 0x008C, 0x008D, 0x008E, 0x008F,
0x0090, 0x0091, 0x0092, 0x0093, 0x0094, 0x0095, 0x0096, 0x0097,
0x0098, 0x0099, 0x009A, 0x009B, 0x009C, 0x009D, 0x009E, 0x009F,
0x00A0, 0x00A1, 0x00A2, 0x00A3, 0x00A4, 0x00A5, 0x00A6, 0x00A7,
0x00A8, 0x00A9, 0x00AA, 0x00AB, 0x00AC, 0x00AD, 0x00AE, 0x00AF,
0x00B0, 0x00B1, 0x00B2, 0x00B3, 0x00B4, 0x00B5, 0x00B6, 0x00B7,
0x00B8, 0x00B9, 0x00BA, 0x00BB, 0x00BC, 0x00BD, 0x00BE, 0x00BF,
0x00C0, 0x00C1, 0x00C2, 0x00C3, 0x00C4, 0x00C5, 0x00C6, 0x00C7,
0x00C8, 0x00C9, 0x00CA, 0x00CB, 0x00CC, 0x00CD, 0x00CE, 0x00CF,
0x00D0, 0x00D1, 0x00D2, 0x00D3, 0x00D4, 0x00D5, 0x00D6, 0x00D7,
0x00D8, 0x00D9, 0x00DA, 0x00DB, 0x00DC, 0x00DD, 0x00DE, 0x00DF,
0x00E0, 0x00E1, 0x00E2, 0x00E3, 0x00E4, 0x00E5, 0x00E6, 0x00E7,
0x00E8, 0x00E9, 0x00EA, 0x00EB, 0x00EC, 0x00ED, 0x00EE, 0x00EF,
0x00F0, 0x00F1, 0x00F2, 0x00F3, 0x00F4, 0x00F5, 0x00F6, 0x00F7,
0x00F8, 0x00F9, 0x00FA, 0x00FB, 0x00FC, 0x00FD, 0x00FE, 0x00FF
];

VT100.prototype.VT100GraphicsMap = [
0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007,
0x0008, 0x0009, 0x000A, 0x000B, 0x000C, 0x000D, 0x000E, 0x000F,
0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017,
0x0018, 0x0019, 0x001A, 0x001B, 0x001C, 0x001D, 0x001E, 0x001F,
0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027,
0x0028, 0x0029, 0x002A, 0x2192, 0x2190, 0x2191, 0x2193, 0x002F,
0x2588, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037,
0x0038, 0x0039, 0x003A, 0x003B, 0x003C, 0x003D, 0x003E, 0x003F,
0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
0x0048, 0x0049, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F,
0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
0x0058, 0x0059, 0x005A, 0x005B, 0x005C, 0x005D, 0x005E, 0x00A0,
0x25C6, 0x2592, 0x2409, 0x240C, 0x240D, 0x240A, 0x00B0, 0x00B1,
0x2591, 0x240B, 0x2518, 0x2510, 0x250C, 0x2514, 0x253C, 0xF800,
0xF801, 0x2500, 0xF803, 0xF804, 0x251C, 0x2524, 0x2534, 0x252C,
0x2502, 0x2264, 0x2265, 0x03C0, 0x2260, 0x00A3, 0x00B7, 0x007F,
0x0080, 0x0081, 0x0082, 0x0083, 0x0084, 0x0085, 0x0086, 0x0087,
0x0088, 0x0089, 0x008A, 0x008B, 0x008C, 0x008D, 0x008E, 0x008F,
0x0090, 0x0091, 0x0092, 0x0093, 0x0094, 0x0095, 0x0096, 0x0097,
0x0098, 0x0099, 0x009A, 0x009B, 0x009C, 0x009D, 0x009E, 0x009F,
0x00A0, 0x00A1, 0x00A2, 0x00A3, 0x00A4, 0x00A5, 0x00A6, 0x00A7,
0x00A8, 0x00A9, 0x00AA, 0x00AB, 0x00AC, 0x00AD, 0x00AE, 0x00AF,
0x00B0, 0x00B1, 0x00B2, 0x00B3, 0x00B4, 0x00B5, 0x00B6, 0x00B7,
0x00B8, 0x00B9, 0x00BA, 0x00BB, 0x00BC, 0x00BD, 0x00BE, 0x00BF,
0x00C0, 0x00C1, 0x00C2, 0x00C3, 0x00C4, 0x00C5, 0x00C6, 0x00C7,
0x00C8, 0x00C9, 0x00CA, 0x00CB, 0x00CC, 0x00CD, 0x00CE, 0x00CF,
0x00D0, 0x00D1, 0x00D2, 0x00D3, 0x00D4, 0x00D5, 0x00D6, 0x00D7,
0x00D8, 0x00D9, 0x00DA, 0x00DB, 0x00DC, 0x00DD, 0x00DE, 0x00DF,
0x00E0, 0x00E1, 0x00E2, 0x00E3, 0x00E4, 0x00E5, 0x00E6, 0x00E7,
0x00E8, 0x00E9, 0x00EA, 0x00EB, 0x00EC, 0x00ED, 0x00EE, 0x00EF,
0x00F0, 0x00F1, 0x00F2, 0x00F3, 0x00F4, 0x00F5, 0x00F6, 0x00F7,
0x00F8, 0x00F9, 0x00FA, 0x00FB, 0x00FC, 0x00FD, 0x00FE, 0x00FF
];

VT100.prototype.CodePage437Map = [
0x0000, 0x263A, 0x263B, 0x2665, 0x2666, 0x2663, 0x2660, 0x2022,
0x25D8, 0x25CB, 0x25D9, 0x2642, 0x2640, 0x266A, 0x266B, 0x263C,
0x25B6, 0x25C0, 0x2195, 0x203C, 0x00B6, 0x00A7, 0x25AC, 0x21A8,
0x2191, 0x2193, 0x2192, 0x2190, 0x221F, 0x2194, 0x25B2, 0x25BC,
0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027,
0x0028, 0x0029, 0x002A, 0x002B, 0x002C, 0x002D, 0x002E, 0x002F,
0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037,
0x0038, 0x0039, 0x003A, 0x003B, 0x003C, 0x003D, 0x003E, 0x003F,
0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
0x0048, 0x0049, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F,
0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
0x0058, 0x0059, 0x005A, 0x005B, 0x005C, 0x005D, 0x005E, 0x005F,
0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067,
0x0068, 0x0069, 0x006A, 0x006B, 0x006C, 0x006D, 0x006E, 0x006F,
0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077,
0x0078, 0x0079, 0x007A, 0x007B, 0x007C, 0x007D, 0x007E, 0x2302,
0x00C7, 0x00FC, 0x00E9, 0x00E2, 0x00E4, 0x00E0, 0x00E5, 0x00E7,
0x00EA, 0x00EB, 0x00E8, 0x00EF, 0x00EE, 0x00EC, 0x00C4, 0x00C5,
0x00C9, 0x00E6, 0x00C6, 0x00F4, 0x00F6, 0x00F2, 0x00FB, 0x00F9,
0x00FF, 0x00D6, 0x00DC, 0x00A2, 0x00A3, 0x00A5, 0x20A7, 0x0192,
0x00E1, 0x00ED, 0x00F3, 0x00FA, 0x00F1, 0x00D1, 0x00AA, 0x00BA,
0x00BF, 0x2310, 0x00AC, 0x00BD, 0x00BC, 0x00A1, 0x00AB, 0x00BB,
0x2591, 0x2592, 0x2593, 0x2502, 0x2524, 0x2561, 0x2562, 0x2556,
0x2555, 0x2563, 0x2551, 0x2557, 0x255D, 0x255C, 0x255B, 0x2510,
0x2514, 0x2534, 0x252C, 0x251C, 0x2500, 0x253C, 0x255E, 0x255F,
0x255A, 0x2554, 0x2569, 0x2566, 0x2560, 0x2550, 0x256C, 0x2567,
0x2568, 0x2564, 0x2565, 0x2559, 0x2558, 0x2552, 0x2553, 0x256B,
0x256A, 0x2518, 0x250C, 0x2588, 0x2584, 0x258C, 0x2590, 0x2580,
0x03B1, 0x00DF, 0x0393, 0x03C0, 0x03A3, 0x03C3, 0x00B5, 0x03C4,
0x03A6, 0x0398, 0x03A9, 0x03B4, 0x221E, 0x03C6, 0x03B5, 0x2229,
0x2261, 0x00B1, 0x2265, 0x2264, 0x2320, 0x2321, 0x00F7, 0x2248,
0x00B0, 0x2219, 0x00B7, 0x221A, 0x207F, 0x00B2, 0x25A0, 0x00A0
];

VT100.prototype.DirectToFontMap = [
0xF000, 0xF001, 0xF002, 0xF003, 0xF004, 0xF005, 0xF006, 0xF007,
0xF008, 0xF009, 0xF00A, 0xF00B, 0xF00C, 0xF00D, 0xF00E, 0xF00F,
0xF010, 0xF011, 0xF012, 0xF013, 0xF014, 0xF015, 0xF016, 0xF017,
0xF018, 0xF019, 0xF01A, 0xF01B, 0xF01C, 0xF01D, 0xF01E, 0xF01F,
0xF020, 0xF021, 0xF022, 0xF023, 0xF024, 0xF025, 0xF026, 0xF027,
0xF028, 0xF029, 0xF02A, 0xF02B, 0xF02C, 0xF02D, 0xF02E, 0xF02F,
0xF030, 0xF031, 0xF032, 0xF033, 0xF034, 0xF035, 0xF036, 0xF037,
0xF038, 0xF039, 0xF03A, 0xF03B, 0xF03C, 0xF03D, 0xF03E, 0xF03F,
0xF040, 0xF041, 0xF042, 0xF043, 0xF044, 0xF045, 0xF046, 0xF047,
0xF048, 0xF049, 0xF04A, 0xF04B, 0xF04C, 0xF04D, 0xF04E, 0xF04F,
0xF050, 0xF051, 0xF052, 0xF053, 0xF054, 0xF055, 0xF056, 0xF057,
0xF058, 0xF059, 0xF05A, 0xF05B, 0xF05C, 0xF05D, 0xF05E, 0xF05F,
0xF060, 0xF061, 0xF062, 0xF063, 0xF064, 0xF065, 0xF066, 0xF067,
0xF068, 0xF069, 0xF06A, 0xF06B, 0xF06C, 0xF06D, 0xF06E, 0xF06F,
0xF070, 0xF071, 0xF072, 0xF073, 0xF074, 0xF075, 0xF076, 0xF077,
0xF078, 0xF079, 0xF07A, 0xF07B, 0xF07C, 0xF07D, 0xF07E, 0xF07F,
0xF080, 0xF081, 0xF082, 0xF083, 0xF084, 0xF085, 0xF086, 0xF087,
0xF088, 0xF089, 0xF08A, 0xF08B, 0xF08C, 0xF08D, 0xF08E, 0xF08F,
0xF090, 0xF091, 0xF092, 0xF093, 0xF094, 0xF095, 0xF096, 0xF097,
0xF098, 0xF099, 0xF09A, 0xF09B, 0xF09C, 0xF09D, 0xF09E, 0xF09F,
0xF0A0, 0xF0A1, 0xF0A2, 0xF0A3, 0xF0A4, 0xF0A5, 0xF0A6, 0xF0A7,
0xF0A8, 0xF0A9, 0xF0AA, 0xF0AB, 0xF0AC, 0xF0AD, 0xF0AE, 0xF0AF,
0xF0B0, 0xF0B1, 0xF0B2, 0xF0B3, 0xF0B4, 0xF0B5, 0xF0B6, 0xF0B7,
0xF0B8, 0xF0B9, 0xF0BA, 0xF0BB, 0xF0BC, 0xF0BD, 0xF0BE, 0xF0BF,
0xF0C0, 0xF0C1, 0xF0C2, 0xF0C3, 0xF0C4, 0xF0C5, 0xF0C6, 0xF0C7,
0xF0C8, 0xF0C9, 0xF0CA, 0xF0CB, 0xF0CC, 0xF0CD, 0xF0CE, 0xF0CF,
0xF0D0, 0xF0D1, 0xF0D2, 0xF0D3, 0xF0D4, 0xF0D5, 0xF0D6, 0xF0D7,
0xF0D8, 0xF0D9, 0xF0DA, 0xF0DB, 0xF0DC, 0xF0DD, 0xF0DE, 0xF0DF,
0xF0E0, 0xF0E1, 0xF0E2, 0xF0E3, 0xF0E4, 0xF0E5, 0xF0E6, 0xF0E7,
0xF0E8, 0xF0E9, 0xF0EA, 0xF0EB, 0xF0EC, 0xF0ED, 0xF0EE, 0xF0EF,
0xF0F0, 0xF0F1, 0xF0F2, 0xF0F3, 0xF0F4, 0xF0F5, 0xF0F6, 0xF0F7,
0xF0F8, 0xF0F9, 0xF0FA, 0xF0FB, 0xF0FC, 0xF0FD, 0xF0FE, 0xF0FF
];

VT100.prototype.ctrlAction = [
  true,  false, false, false, false, false, false, true,
  true,  true,  true,  true,  true,  true,  true,  true,
  false, false, false, false, false, false, false, false,
  true,  false, true,  true,  false, false, false, false
];

VT100.prototype.ctrlAlways = [
  true,  false, false, false, false, false, false, false,
  true,  false, true,  false, true,  true,  true,  true,
  false, false, false, false, false, false, false, false,
  false, false, false, true,  false, false, false, false
];