[Dynapi-Help] DynAPI and Prototype

[Jesse V. <je...@6t...>]

I'm playing around with Prototype (http://prototype.conio.net/) and it 
seems to conflict with DynAPI.  I wanted to use prototype for ajax 
functionality, but still use DynAPI for all it's DynAPI goodness.  Has 
anyone played around with Prototype before?  Any idea what this error 
would be from?  I've added the prototype.js to the bottom of the email.

This is my js code:

        <script src="../js/prototype.js"></script>
        <script src="../js/dynapi/dynapi.js"></script>
        <script language="Javascript">
            dynapi.library.setPath('../js/dynapi/');
            dynapi.library.include('dynapi.api');
            dynapi.library.include('dynapi.api.ext.DynLayerInline');
            dynapi.library.include('Fader');
        </script>

And I get this error in Firefox:

Error: n.indexOf is not a function
Source File: http://localhost:8080/agentscape/js/dynapi/dynapi.js
Line: 388

If I don't do the DynAPI includes, Prototype works fine.  If I don't do 
the Prototype include, DynAPI works fine.  So I'm assuming it's the mix 
of them that's the problem, but I'm not sure where.

Any ideas of what's going on or how to avoid it would be appreciated.

Thanks in advance,
    Jesse


prototype.js:
/*  Prototype JavaScript framework, version 1.3.1
 *  (c) 2005 Sam Stephenson <sa...@co...>
 *
 *  THIS FILE IS AUTOMATICALLY GENERATED. When sending patches, please diff
 *  against the source tree, available from the Prototype darcs repository.
 *
 *  Prototype is freely distributable under the terms of an MIT-style 
license.
 *
 *  For details, see the Prototype web site: http://prototype.conio.net/
 *
/*--------------------------------------------------------------------------*/

var Prototype = {
  Version: '1.3.1',
  emptyFunction: function() {}
}

var Class = {
  create: function() {
    return function() {
      this.initialize.apply(this, arguments);
    }
  }
}

var Abstract = new Object();

Object.extend = function(destination, source) {
  for (property in source) {
    destination[property] = source[property];
  }
  return destination;
}

Object.prototype.extend = function(object) {
  return Object.extend.apply(this, [this, object]);
}

Function.prototype.bind = function(object) {
  var __method = this;
  return function() {
    __method.apply(object, arguments);
  }
}

Function.prototype.bindAsEventListener = function(object) {
  var __method = this;
  return function(event) {
    __method.call(object, event || window.event);
  }
}

Number.prototype.toColorPart = function() {
  var digits = this.toString(16);
  if (this < 16) return '0' + digits;
  return digits;
}

var Try = {
  these: function() {
    var returnValue;

    for (var i = 0; i < arguments.length; i++) {
      var lambda = arguments[i];
      try {
        returnValue = lambda();
        break;
      } catch (e) {}
    }

    return returnValue;
  }
}

/*--------------------------------------------------------------------------*/

var PeriodicalExecuter = Class.create();
PeriodicalExecuter.prototype = {
  initialize: function(callback, frequency) {
    this.callback = callback;
    this.frequency = frequency;
    this.currentlyExecuting = false;

    this.registerCallback();
  },

  registerCallback: function() {
    setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);
  },

  onTimerEvent: function() {
    if (!this.currentlyExecuting) {
      try {
        this.currentlyExecuting = true;
        this.callback();
      } finally {
        this.currentlyExecuting = false;
      }
    }
  }
}

/*--------------------------------------------------------------------------*/

function $() {
  var elements = new Array();

  for (var i = 0; i < arguments.length; i++) {
    var element = arguments[i];
    if (typeof element == 'string')
      element = document.getElementById(element);

    if (arguments.length == 1)
      return element;

    elements.push(element);
  }

  return elements;
}

if (!Array.prototype.push) {
  Array.prototype.push = function() {
        var startLength = this.length;
        for (var i = 0; i < arguments.length; i++)
      this[startLength + i] = arguments[i];
      return this.length;
  }
}

if (!Function.prototype.apply) {
  // Based on code from http://www.youngpup.net/
  Function.prototype.apply = function(object, parameters) {
    var parameterStrings = new Array();
    if (!object)     object = window;
    if (!parameters) parameters = new Array();
   
    for (var i = 0; i < parameters.length; i++)
      parameterStrings[i] = 'parameters[' + i + ']';
   
    object.__apply__ = this;
    var result = eval('object.__apply__(' +
      parameterStrings.join(', ') + ')');
    object.__apply__ = null;
   
    return result;
  }
}

String.prototype.extend({
  stripTags: function() {
    return this.replace(/<\/?[^>]+>/gi, '');
  },

  escapeHTML: function() {
    var div = document.createElement('div');
    var text = document.createTextNode(this);
    div.appendChild(text);
    return div.innerHTML;
  },

  unescapeHTML: function() {
    var div = document.createElement('div');
    div.innerHTML = this.stripTags();
    return div.childNodes[0].nodeValue;
  }
});

var Ajax = {
  getTransport: function() {
    return Try.these(
      function() {return new ActiveXObject('Msxml2.XMLHTTP')},
      function() {return new ActiveXObject('Microsoft.XMLHTTP')},
      function() {return new XMLHttpRequest()}
    ) || false;
  }
}

Ajax.Base = function() {};
Ajax.Base.prototype = {
  setOptions: function(options) {
    this.options = {
      method:       'post',
      asynchronous: true,
      parameters:   ''
    }.extend(options || {});
  },

  responseIsSuccess: function() {
    return this.transport.status == undefined
        || this.transport.status == 0
        || (this.transport.status >= 200 && this.transport.status < 300);
  },

  responseIsFailure: function() {
    return !this.responseIsSuccess();
  }
}

Ajax.Request = Class.create();
Ajax.Request.Events =
  ['Uninitialized', 'Loading', 'Loaded', 'Interactive', 'Complete'];

Ajax.Request.prototype = (new Ajax.Base()).extend({
  initialize: function(url, options) {
    this.transport = Ajax.getTransport();
    this.setOptions(options);
    this.request(url);
  },

  request: function(url) {
    var parameters = this.options.parameters || '';
    if (parameters.length > 0) parameters += '&_=';

    try {
      if (this.options.method == 'get')
        url += '?' + parameters;

      this.transport.open(this.options.method, url,
        this.options.asynchronous);

      if (this.options.asynchronous) {
        this.transport.onreadystatechange = this.onStateChange.bind(this);
        setTimeout((function() 
{this.respondToReadyState(1)}).bind(this), 10);
      }

      this.setRequestHeaders();

      var body = this.options.postBody ? this.options.postBody : parameters;
      this.transport.send(this.options.method == 'post' ? body : null);

    } catch (e) {
    }
  },

  setRequestHeaders: function() {
    var requestHeaders =
      ['X-Requested-With', 'XMLHttpRequest',
       'X-Prototype-Version', Prototype.Version];

    if (this.options.method == 'post') {
      requestHeaders.push('Content-type',
        'application/x-www-form-urlencoded');

      /* Force "Connection: close" for Mozilla browsers to work around
       * a bug where XMLHttpReqeuest sends an incorrect Content-length
       * header. See Mozilla Bugzilla #246651.
       */
      if (this.transport.overrideMimeType)
        requestHeaders.push('Connection', 'close');
    }

    if (this.options.requestHeaders)
      requestHeaders.push.apply(requestHeaders, 
this.options.requestHeaders);

    for (var i = 0; i < requestHeaders.length; i += 2)
      this.transport.setRequestHeader(requestHeaders[i], 
requestHeaders[i+1]);
  },

  onStateChange: function() {
    var readyState = this.transport.readyState;
    if (readyState != 1)
      this.respondToReadyState(this.transport.readyState);
  },

  respondToReadyState: function(readyState) {
    var event = Ajax.Request.Events[readyState];

    if (event == 'Complete')
      (this.options['on' + this.transport.status]
       || this.options['on' + (this.responseIsSuccess() ? 'Success' : 
'Failure')]
       || Prototype.emptyFunction)(this.transport);

    (this.options['on' + event] || Prototype.emptyFunction)(this.transport);

    /* Avoid memory leak in MSIE: clean up the oncomplete event handler */
    if (event == 'Complete')
      this.transport.onreadystatechange = Prototype.emptyFunction;
  }
});

Ajax.Updater = Class.create();
Ajax.Updater.ScriptFragment = '(?:<script.*?>)((\n|.)*?)(?:<\/script>)';

Ajax.Updater.prototype.extend(Ajax.Request.prototype).extend({
  initialize: function(container, url, options) {
    this.containers = {
      success: container.success ? $(container.success) : $(container),
      failure: container.failure ? $(container.failure) :
        (container.success ? null : $(container))
    }

    this.transport = Ajax.getTransport();
    this.setOptions(options);

    var onComplete = this.options.onComplete || Prototype.emptyFunction;
    this.options.onComplete = (function() {
      this.updateContent();
      onComplete(this.transport);
    }).bind(this);

    this.request(url);
  },

  updateContent: function() {
    var receiver = this.responseIsSuccess() ?
      this.containers.success : this.containers.failure;

    var match    = new RegExp(Ajax.Updater.ScriptFragment, 'img');
    var response = this.transport.responseText.replace(match, '');
    var scripts  = this.transport.responseText.match(match);

    if (receiver) {
      if (this.options.insertion) {
        new this.options.insertion(receiver, response);
      } else {
        receiver.innerHTML = response;
      }
    }

    if (this.responseIsSuccess()) {
      if (this.onComplete)
        setTimeout((function() {this.onComplete(
          this.transport)}).bind(this), 10);
    }

    if (this.options.evalScripts && scripts) {
      match = new RegExp(Ajax.Updater.ScriptFragment, 'im');
      setTimeout((function() {
        for (var i = 0; i < scripts.length; i++)
          eval(scripts[i].match(match)[1]);
      }).bind(this), 10);
    }
  }
});

Ajax.PeriodicalUpdater = Class.create();
Ajax.PeriodicalUpdater.prototype = (new Ajax.Base()).extend({
  initialize: function(container, url, options) {
    this.setOptions(options);
    this.onComplete = this.options.onComplete;

    this.frequency = (this.options.frequency || 2);
    this.decay = 1;

    this.updater = {};
    this.container = container;
    this.url = url;

    this.start();
  },

  start: function() {
    this.options.onComplete = this.updateComplete.bind(this);
    this.onTimerEvent();
  },

  stop: function() {
    this.updater.onComplete = undefined;
    clearTimeout(this.timer);
    (this.onComplete || Ajax.emptyFunction).apply(this, arguments);
  },

  updateComplete: function(request) {
    if (this.options.decay) {
      this.decay = (request.responseText == this.lastText ?
        this.decay * this.options.decay : 1);

      this.lastText = request.responseText;
    }
    this.timer = setTimeout(this.onTimerEvent.bind(this),
      this.decay * this.frequency * 1000);
  },

  onTimerEvent: function() {
    this.updater = new Ajax.Updater(this.container, this.url, this.options);
  }
});

document.getElementsByClassName = function(className) {
  var children = document.getElementsByTagName('*') || document.all;
  var elements = new Array();
 
  for (var i = 0; i < children.length; i++) {
    var child = children[i];
    var classNames = child.className.split(' ');
    for (var j = 0; j < classNames.length; j++) {
      if (classNames[j] == className) {
        elements.push(child);
        break;
      }
    }
  }
 
  return elements;
}

/*--------------------------------------------------------------------------*/

if (!window.Element) {
  var Element = new Object();
}

Object.extend(Element, {
  toggle: function() {
    for (var i = 0; i < arguments.length; i++) {
      var element = $(arguments[i]);
      element.style.display =
        (element.style.display == 'none' ? '' : 'none');
    }
  },

  hide: function() {
    for (var i = 0; i < arguments.length; i++) {
      var element = $(arguments[i]);
      element.style.display = 'none';
    }
  },

  show: function() {
    for (var i = 0; i < arguments.length; i++) {
      var element = $(arguments[i]);
      element.style.display = '';
    }
  },

  remove: function(element) {
    element = $(element);
    element.parentNode.removeChild(element);
  },
  
  getHeight: function(element) {
    element = $(element);
    return element.offsetHeight;
  },

  hasClassName: function(element, className) {
    element = $(element);
    if (!element)
      return;
    var a = element.className.split(' ');
    for (var i = 0; i < a.length; i++) {
      if (a[i] == className)
        return true;
    }
    return false;
  },

  addClassName: function(element, className) {
    element = $(element);
    Element.removeClassName(element, className);
    element.className += ' ' + className;
  },

  removeClassName: function(element, className) {
    element = $(element);
    if (!element)
      return;
    var newClassName = '';
    var a = element.className.split(' ');
    for (var i = 0; i < a.length; i++) {
      if (a[i] != className) {
        if (i > 0)
          newClassName += ' ';
        newClassName += a[i];
      }
    }
    element.className = newClassName;
  },
 
  // removes whitespace-only text node children
  cleanWhitespace: function(element) {
    var element = $(element);
    for (var i = 0; i < element.childNodes.length; i++) {
      var node = element.childNodes[i];
      if (node.nodeType == 3 && !/\S/.test(node.nodeValue))
        Element.remove(node);
    }
  }
});

var Toggle = new Object();
Toggle.display = Element.toggle;

/*--------------------------------------------------------------------------*/

Abstract.Insertion = function(adjacency) {
  this.adjacency = adjacency;
}

Abstract.Insertion.prototype = {
  initialize: function(element, content) {
    this.element = $(element);
    this.content = content;
   
    if (this.adjacency && this.element.insertAdjacentHTML) {
      this.element.insertAdjacentHTML(this.adjacency, this.content);
    } else {
      this.range = this.element.ownerDocument.createRange();
      if (this.initializeRange) this.initializeRange();
      this.fragment = this.range.createContextualFragment(this.content);
      this.insertContent();
    }
  }
}

var Insertion = new Object();

Insertion.Before = Class.create();
Insertion.Before.prototype = (new 
Abstract.Insertion('beforeBegin')).extend({
  initializeRange: function() {
    this.range.setStartBefore(this.element);
  },
 
  insertContent: function() {
    this.element.parentNode.insertBefore(this.fragment, this.element);
  }
});

Insertion.Top = Class.create();
Insertion.Top.prototype = (new Abstract.Insertion('afterBegin')).extend({
  initializeRange: function() {
    this.range.selectNodeContents(this.element);
    this.range.collapse(true);
  },
 
  insertContent: function() { 
    this.element.insertBefore(this.fragment, this.element.firstChild);
  }
});

Insertion.Bottom = Class.create();
Insertion.Bottom.prototype = (new Abstract.Insertion('beforeEnd')).extend({
  initializeRange: function() {
    this.range.selectNodeContents(this.element);
    this.range.collapse(this.element);
  },
 
  insertContent: function() {
    this.element.appendChild(this.fragment);
  }
});

Insertion.After = Class.create();
Insertion.After.prototype = (new Abstract.Insertion('afterEnd')).extend({
  initializeRange: function() {
    this.range.setStartAfter(this.element);
  },
 
  insertContent: function() {
    this.element.parentNode.insertBefore(this.fragment,
      this.element.nextSibling);
  }
});

var Field = {
  clear: function() {
    for (var i = 0; i < arguments.length; i++)
      $(arguments[i]).value = '';
  },

  focus: function(element) {
    $(element).focus();
  },
 
  present: function() {
    for (var i = 0; i < arguments.length; i++)
      if ($(arguments[i]).value == '') return false;
    return true;
  },
 
  select: function(element) {
    $(element).select();
  },
  
  activate: function(element) {
    $(element).focus();
    $(element).select();
  }
}

/*--------------------------------------------------------------------------*/

var Form = {
  serialize: function(form) {
    var elements = Form.getElements($(form));
    var queryComponents = new Array();
   
    for (var i = 0; i < elements.length; i++) {
      var queryComponent = Form.Element.serialize(elements[i]);
      if (queryComponent)
        queryComponents.push(queryComponent);
    }
   
    return queryComponents.join('&');
  },
 
  getElements: function(form) {
    var form = $(form);
    var elements = new Array();

    for (tagName in Form.Element.Serializers) {
      var tagElements = form.getElementsByTagName(tagName);
      for (var j = 0; j < tagElements.length; j++)
        elements.push(tagElements[j]);
    }
    return elements;
  },
 
  getInputs: function(form, typeName, name) {
    var form = $(form);
    var inputs = form.getElementsByTagName('input');
   
    if (!typeName && !name)
      return inputs;
     
    var matchingInputs = new Array();
    for (var i = 0; i < inputs.length; i++) {
      var input = inputs[i];
      if ((typeName && input.type != typeName) ||
          (name && input.name != name))
        continue;
      matchingInputs.push(input);
    }

    return matchingInputs;
  },

  disable: function(form) {
    var elements = Form.getElements(form);
    for (var i = 0; i < elements.length; i++) {
      var element = elements[i];
      element.blur();
      element.disabled = 'true';
    }
  },

  enable: function(form) {
    var elements = Form.getElements(form);
    for (var i = 0; i < elements.length; i++) {
      var element = elements[i];
      element.disabled = '';
    }
  },

  focusFirstElement: function(form) {
    var form = $(form);
    var elements = Form.getElements(form);
    for (var i = 0; i < elements.length; i++) {
      var element = elements[i];
      if (element.type != 'hidden' && !element.disabled) {
        Field.activate(element);
        break;
      }
    }
  },

  reset: function(form) {
    $(form).reset();
  }
}

Form.Element = {
  serialize: function(element) {
    var element = $(element);
    var method = element.tagName.toLowerCase();
    var parameter = Form.Element.Serializers[method](element);
   
    if (parameter)
      return encodeURIComponent(parameter[0]) + '=' +
        encodeURIComponent(parameter[1]);                  
  },
 
  getValue: function(element) {
    var element = $(element);
    var method = element.tagName.toLowerCase();
    var parameter = Form.Element.Serializers[method](element);
   
    if (parameter)
      return parameter[1];
  }
}

Form.Element.Serializers = {
  input: function(element) {
    switch (element.type.toLowerCase()) {
      case 'submit':
      case 'hidden':
      case 'password':
      case 'text':
        return Form.Element.Serializers.textarea(element);
      case 'checkbox': 
      case 'radio':
        return Form.Element.Serializers.inputSelector(element);
    }
    return false;
  },

  inputSelector: function(element) {
    if (element.checked)
      return [element.name, element.value];
  },

  textarea: function(element) {
    return [element.name, element.value];
  },

  select: function(element) {
    var value = '';
    if (element.type == 'select-one') {
      var index = element.selectedIndex;
      if (index >= 0)
        value = element.options[index].value || element.options[index].text;
    } else {
      value = new Array();
      for (var i = 0; i < element.length; i++) {
        var opt = element.options[i];
        if (opt.selected)
          value.push(opt.value || opt.text);
      }
    }
    return [element.name, value];
  }
}

/*--------------------------------------------------------------------------*/

var $F = Form.Element.getValue;

/*--------------------------------------------------------------------------*/

Abstract.TimedObserver = function() {}
Abstract.TimedObserver.prototype = {
  initialize: function(element, frequency, callback) {
    this.frequency = frequency;
    this.element   = $(element);
    this.callback  = callback;
   
    this.lastValue = this.getValue();
    this.registerCallback();
  },
 
  registerCallback: function() {
    setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);
  },
 
  onTimerEvent: function() {
    var value = this.getValue();
    if (this.lastValue != value) {
      this.callback(this.element, value);
      this.lastValue = value;
    }
  }
}

Form.Element.Observer = Class.create();
Form.Element.Observer.prototype = (new Abstract.TimedObserver()).extend({
  getValue: function() {
    return Form.Element.getValue(this.element);
  }
});

Form.Observer = Class.create();
Form.Observer.prototype = (new Abstract.TimedObserver()).extend({
  getValue: function() {
    return Form.serialize(this.element);
  }
});

/*--------------------------------------------------------------------------*/

Abstract.EventObserver = function() {}
Abstract.EventObserver.prototype = {
  initialize: function(element, callback) {
    this.element  = $(element);
    this.callback = callback;
   
    this.lastValue = this.getValue();
    if (this.element.tagName.toLowerCase() == 'form')
      this.registerFormCallbacks();
    else
      this.registerCallback(this.element);
  },
 
  onElementEvent: function() {
    var value = this.getValue();
    if (this.lastValue != value) {
      this.callback(this.element, value);
      this.lastValue = value;
    }
  },
 
  registerFormCallbacks: function() {
    var elements = Form.getElements(this.element);
    for (var i = 0; i < elements.length; i++)
      this.registerCallback(elements[i]);
  },
 
  registerCallback: function(element) {
    if (element.type) {
      switch (element.type.toLowerCase()) {
        case 'checkbox': 
        case 'radio':
          element.target = this;
          element.prev_onclick = element.onclick || Prototype.emptyFunction;
          element.onclick = function() {
            this.prev_onclick();
            this.target.onElementEvent();
          }
          break;
        case 'password':
        case 'text':
        case 'textarea':
        case 'select-one':
        case 'select-multiple':
          element.target = this;
          element.prev_onchange = element.onchange || 
Prototype.emptyFunction;
          element.onchange = function() {
            this.prev_onchange();
            this.target.onElementEvent();
          }
          break;
      }
    }   
  }
}

Form.Element.EventObserver = Class.create();
Form.Element.EventObserver.prototype = (new 
Abstract.EventObserver()).extend({
  getValue: function() {
    return Form.Element.getValue(this.element);
  }
});

Form.EventObserver = Class.create();
Form.EventObserver.prototype = (new Abstract.EventObserver()).extend({
  getValue: function() {
    return Form.serialize(this.element);
  }
});


if (!window.Event) {
  var Event = new Object();
}

Object.extend(Event, {
  KEY_BACKSPACE: 8,
  KEY_TAB:       9,
  KEY_RETURN:   13,
  KEY_ESC:      27,
  KEY_LEFT:     37,
  KEY_UP:       38,
  KEY_RIGHT:    39,
  KEY_DOWN:     40,
  KEY_DELETE:   46,

  element: function(event) {
    return event.target || event.srcElement;
  },

  isLeftClick: function(event) {
    return (((event.which) && (event.which == 1)) ||
            ((event.button) && (event.button == 1)));
  },

  pointerX: function(event) {
    return event.pageX || (event.clientX +
      (document.documentElement.scrollLeft || document.body.scrollLeft));
  },

  pointerY: function(event) {
    return event.pageY || (event.clientY +
      (document.documentElement.scrollTop || document.body.scrollTop));
  },

  stop: function(event) {
    if (event.preventDefault) {
      event.preventDefault();
      event.stopPropagation();
    } else {
      event.returnValue = false;
    }
  },

  // find the first node with the given tagName, starting from the
  // node the event was triggered on; traverses the DOM upwards
  findElement: function(event, tagName) {
    var element = Event.element(event);
    while (element.parentNode && (!element.tagName ||
        (element.tagName.toUpperCase() != tagName.toUpperCase())))
      element = element.parentNode;
    return element;
  },

  observers: false,
 
  _observeAndCache: function(element, name, observer, useCapture) {
    if (!this.observers) this.observers = [];
    if (element.addEventListener) {
      this.observers.push([element, name, observer, useCapture]);
      element.addEventListener(name, observer, useCapture);
    } else if (element.attachEvent) {
      this.observers.push([element, name, observer, useCapture]);
      element.attachEvent('on' + name, observer);
    }
  },
 
  unloadCache: function() {
    if (!Event.observers) return;
    for (var i = 0; i < Event.observers.length; i++) {
      Event.stopObserving.apply(this, Event.observers[i]);
      Event.observers[i][0] = null;
    }
    Event.observers = false;
  },

  observe: function(element, name, observer, useCapture) {
    var element = $(element);
    useCapture = useCapture || false;
   
    if (name == 'keypress' &&
        ((navigator.appVersion.indexOf('AppleWebKit') > 0)
        || element.attachEvent))
      name = 'keydown';
   
    this._observeAndCache(element, name, observer, useCapture);
  },

  stopObserving: function(element, name, observer, useCapture) {
    var element = $(element);
    useCapture = useCapture || false;
   
    if (name == 'keypress' &&
        ((navigator.appVersion.indexOf('AppleWebKit') > 0)
        || element.detachEvent))
      name = 'keydown';
   
    if (element.removeEventListener) {
      element.removeEventListener(name, observer, useCapture);
    } else if (element.detachEvent) {
      element.detachEvent('on' + name, observer);
    }
  }
});

/* prevent memory leaks in IE */
Event.observe(window, 'unload', Event.unloadCache, false);

var Position = {

  // set to true if needed, warning: firefox performance problems
  // NOT neeeded for page scrolling, only if draggable contained in
  // scrollable elements
  includeScrollOffsets: false,

  // must be called before calling withinIncludingScrolloffset, every 
time the
  // page is scrolled
  prepare: function() {
    this.deltaX =  window.pageXOffset
                || document.documentElement.scrollLeft
                || document.body.scrollLeft
                || 0;
    this.deltaY =  window.pageYOffset
                || document.documentElement.scrollTop
                || document.body.scrollTop
                || 0;
  },

  realOffset: function(element) {
    var valueT = 0, valueL = 0;
    do {
      valueT += element.scrollTop  || 0;
      valueL += element.scrollLeft || 0;
      element = element.parentNode;
    } while (element);
    return [valueL, valueT];
  },

  cumulativeOffset: function(element) {
    var valueT = 0, valueL = 0;
    do {
      valueT += element.offsetTop  || 0;
      valueL += element.offsetLeft || 0;
      element = element.offsetParent;
    } while (element);
    return [valueL, valueT];
  },

  // caches x/y coordinate pair to use with overlap
  within: function(element, x, y) {
    if (this.includeScrollOffsets)
      return this.withinIncludingScrolloffsets(element, x, y);
    this.xcomp = x;
    this.ycomp = y;
    this.offset = this.cumulativeOffset(element);

    return (y >= this.offset[1] &&
            y <  this.offset[1] + element.offsetHeight &&
            x >= this.offset[0] &&
            x <  this.offset[0] + element.offsetWidth);
  },

  withinIncludingScrolloffsets: function(element, x, y) {
    var offsetcache = this.realOffset(element);

    this.xcomp = x + offsetcache[0] - this.deltaX;
    this.ycomp = y + offsetcache[1] - this.deltaY;
    this.offset = this.cumulativeOffset(element);

    return (this.ycomp >= this.offset[1] &&
            this.ycomp <  this.offset[1] + element.offsetHeight &&
            this.xcomp >= this.offset[0] &&
            this.xcomp <  this.offset[0] + element.offsetWidth);
  },

  // within must be called directly before
  overlap: function(mode, element) { 
    if (!mode) return 0; 
    if (mode == 'vertical')
      return ((this.offset[1] + element.offsetHeight) - this.ycomp) /
        element.offsetHeight;
    if (mode == 'horizontal')
      return ((this.offset[0] + element.offsetWidth) - this.xcomp) /
        element.offsetWidth;
  },

  clone: function(source, target) {
    source = $(source);
    target = $(target);
    target.style.position = 'absolute';
    var offsets = this.cumulativeOffset(source);
    target.style.top    = offsets[1] + 'px';
    target.style.left   = offsets[0] + 'px';
    target.style.width  = source.offsetWidth + 'px';
    target.style.height = source.offsetHeight + 'px';
  }
}