function $(element) {
  if (arguments.length > 1) {
    for (var i = 0, elements = [], length = arguments.length; i < length; i++)
      elements.push($(arguments[i]));
    return elements;
  }
  if (typeof element == 'string')
    element = document.getElementById(element);
  return Element.extend(element);
}

if (Prototype.BrowserFeatures.XPath) {
  document._getElementsByXPath = function(expression, parentElement) {
    var results = [];
    var query = document.evaluate(expression, $(parentElement) || document,
      null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
    for (var i = 0, length = query.snapshotLength; i < length; i++)
      results.push(query.snapshotItem(i));
    return results;
  };
}

document.getElementsByClassName = function(className, parentElement) {
  if (Prototype.BrowserFeatures.XPath) {
    var q = ".//*[contains(concat(' ', @class, ' '), ' " + className + " ')]";
    return document._getElementsByXPath(q, parentElement);
  } else {
    var children = ($(parentElement) || document.body).getElementsByTagName('*');
    var elements = [], child;
    for (var i = 0, length = children.length; i < length; i++) {
      child = children[i];
      if (Element.hasClassName(child, className))
        elements.push(Element.extend(child));
    }
    return elements;
  }
};

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

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

Element.extend = function(element) {
  if (!element || _nativeExtensions || element.nodeType == 3) return element;
  
  if (!element._extended && element.tagName && element != window) {
    var methods = Object.clone(Element.Methods), cache = Element.extend.cache;
    
    if (element.tagName == 'FORM')
      Object.extend(methods, Form.Methods);
    if (['INPUT', 'TEXTAREA', 'SELECT'].include(element.tagName)) 
      Object.extend(methods, Form.Element.Methods);
    
    Object.extend(methods, Element.Methods.Simulated);
      
    for (var property in methods) {
      var value = methods[property];
      if (typeof value == 'function' && !(property in element))
        element[property] = cache.findOrStore(value);
    }
  }
  
  element._extended = true;
  return element;
};

Element.extend.cache = {
  findOrStore: function(value) {
    return this[value] = this[value] || function() {
      return value.apply(null, [this].concat($A(arguments)));
    }
  }
};

Element.Methods = {
  visible: function(element) {
    return $(element).style.display != 'none';
  },
  
  toggle: function(element) {
    element = $(element);
    Element[Element.visible(element) ? 'hide' : 'show'](element);
    return element;
  },

  hide: function(element) {
    $(element).style.display = 'none';
    return element;
  },
  
  show: function(element) {
    $(element).style.display = '';
    return element;
  },

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

  update: function(element, html) {
    html = typeof html == 'undefined' ? '' : html.toString();
    $(element).innerHTML = html.stripScripts();
    setTimeout(function() {html.evalScripts()}, 10);
    return element;
  },
  
  replace: function(element, html) {
    element = $(element);
    html = typeof html == 'undefined' ? '' : html.toString();
    if (element.outerHTML) {
      element.outerHTML = html.stripScripts();
    } else {
      var range = element.ownerDocument.createRange();
      range.selectNodeContents(element);
      element.parentNode.replaceChild(
        range.createContextualFragment(html.stripScripts()), element);
    }
    setTimeout(function() {html.evalScripts()}, 10);
    return element;
  },
  
  inspect: function(element) {
    element = $(element);
    var result = '<' + element.tagName.toLowerCase();
    $H({'id': 'id', 'className': 'class'}).each(function(pair) {
      var property = pair.first(), attribute = pair.last();
      var value = (element[property] || '').toString();
      if (value) result += ' ' + attribute + '=' + value.inspect(true);
    });
    return result + '>';
  },
  
  recursivelyCollect: function(element, property) {
    element = $(element);
    var elements = [];
    while (element = element[property])
      if (element.nodeType == 1)
        elements.push(Element.extend(element));
    return elements;
  },
  
  ancestors: function(element) {
    return $(element).recursivelyCollect('parentNode');
  },
  
  descendants: function(element) {
    return $A($(element).getElementsByTagName('*'));
  },
  
  immediateDescendants: function(element) {
    if (!(element = $(element).firstChild)) return [];
    while (element && element.nodeType != 1) element = element.nextSibling;
    if (element) return [element].concat($(element).nextSiblings());
    return [];
  },

  previousSiblings: function(element) {
    return $(element).recursivelyCollect('previousSibling');
  },
  
  nextSiblings: function(element) {
    return $(element).recursivelyCollect('nextSibling');
  },
  
  siblings: function(element) {
    element = $(element);
    return element.previousSiblings().reverse().concat(element.nextSiblings());
  },
  
  match: function(element, selector) {
    if (typeof selector == 'string')
      selector = new Selector(selector);
    return selector.match($(element));
  },
  
  up: function(element, expression, index) {
    return Selector.findElement($(element).ancestors(), expression, index);
  },
  
  down: function(element, expression, index) {
    return Selector.findElement($(element).descendants(), expression, index);
  },

  previous: function(element, expression, index) {
    return Selector.findElement($(element).previousSiblings(), expression, index);
  },
  
  next: function(element, expression, index) {
    return Selector.findElement($(element).nextSiblings(), expression, index);
  },
  
  getElementsBySelector: function() {
    var args = $A(arguments), element = $(args.shift());
    return Selector.findChildElements(element, args);
  },
  
  getElementsByClassName: function(element, className) {
    return document.getElementsByClassName(className, element);
  },
  
  readAttribute: function(element, name) {
    element = $(element);
    if (document.all && !window.opera) {
      var t = Element._attributeTranslations;
      if (t.values[name]) return t.values[name](element, name);
      if (t.names[name])  name = t.names[name];
      var attribute = element.attributes[name];
      if(attribute) return attribute.nodeValue;
    }    
    return element.getAttribute(name);
  },
  
  getHeight: function(element) {
    return $(element).getDimensions().height; 
  },
  
  getWidth: function(element) {
    return $(element).getDimensions().width; 
  },
  
  classNames: function(element) {
    return new Element.ClassNames(element);
  },

  hasClassName: function(element, className) {
    if (!(element = $(element))) return;
    var elementClassName = element.className;
    if (elementClassName.length == 0) return false;
    if (elementClassName == className || 
        elementClassName.match(new RegExp("(^|\\s)" + className + "(\\s|$)")))
      return true;
    return false;
  },

  addClassName: function(element, className) {
    if (!(element = $(element))) return;
    Element.classNames(element).add(className);
    return element;
  },

  removeClassName: function(element, className) {
    if (!(element = $(element))) return;
    Element.classNames(element).remove(className);
    return element;
  },
  
  toggleClassName: function(element, className) {
    if (!(element = $(element))) return;
    Element.classNames(element)[element.hasClassName(className) ? 'remove' : 'add'](className);
    return element;
  },
  
  observe: function() {
    Event.observe.apply(Event, arguments);
    return $A(arguments).first();
  },
  
  stopObserving: function() {
    Event.stopObserving.apply(Event, arguments);
    return $A(arguments).first();
  },
  
  // removes whitespace-only text node children
  cleanWhitespace: function(element) {
    element = $(element);
    var node = element.firstChild;
    while (node) {
      var nextNode = node.nextSibling;
      if (node.nodeType == 3 && !/\S/.test(node.nodeValue))
        element.removeChild(node);
      node = nextNode;
    }
    return element;
  },
  
  empty: function(element) {
    return $(element).innerHTML.match(/^\s*$/);
  },
  
  descendantOf: function(element, ancestor) {
    element = $(element), ancestor = $(ancestor);
    while (element = element.parentNode)
      if (element == ancestor) return true;
    return false;
  },
  
  scrollTo: function(element) {
    element = $(element);
    var pos = Position.cumulativeOffset(element);
    window.scrollTo(pos[0], pos[1]);
    return element;
  },
  
  getStyle: function(element, style) {
    element = $(element);
    if (['float','cssFloat'].include(style))
      style = (typeof element.style.styleFloat != 'undefined' ? 'styleFloat' : 'cssFloat');
    style = style.camelize();
    var value = element.style[style];
    if (!value) {
      if (document.defaultView && document.defaultView.getComputedStyle) {
        var css = document.defaultView.getComputedStyle(element, null);
        value = css ? css[style] : null;
      } else if (element.currentStyle) {
        value = element.currentStyle[style];
      }
    }
    
    if((value == 'auto') && ['width','height'].include(style) && (element.getStyle('display') != 'none'))
      value = element['offset'+style.capitalize()] + 'px';
    
    if (window.opera && ['left', 'top', 'right', 'bottom'].include(style))
      if (Element.getStyle(element, 'position') == 'static') value = 'auto';
    if(style == 'opacity') {
      if(value) return parseFloat(value);
      if(value = (element.getStyle('filter') || '').match(/alpha\(opacity=(.*)\)/))  
        if(value[1]) return parseFloat(value[1]) / 100;  
      return 1.0; 
    }
    return value == 'auto' ? null : value;
  },
  
  setStyle: function(element, style) {
    element = $(element);
    for (var name in style) {
      var value = style[name];
      if(name == 'opacity') {
        if (value == 1) {
          value = (/Gecko/.test(navigator.userAgent) &&
            !/Konqueror|Safari|KHTML/.test(navigator.userAgent)) ? 0.999999 : 1.0;
          if(/MSIE/.test(navigator.userAgent) && !window.opera)
            element.style.filter = element.getStyle('filter').replace(/alpha\([^\)]*\)/gi,'');
        } else if(value === '') {
          if(/MSIE/.test(navigator.userAgent) && !window.opera)
            element.style.filter = element.getStyle('filter').replace(/alpha\([^\)]*\)/gi,'');
        } else {
          if(value < 0.00001) value = 0;  
          if(/MSIE/.test(navigator.userAgent) && !window.opera)
            element.style.filter = element.getStyle('filter').replace(/alpha\([^\)]*\)/gi,'') +
              'alpha(opacity='+value*100+')';
        }
      } else if(['float','cssFloat'].include(name)) name = (typeof element.style.styleFloat != 'undefined') ? 'styleFloat' : 'cssFloat';
      element.style[name.camelize()] = value;
    }
    return element;
  },
  
  getDimensions: function(element) {
    element = $(element);
    var display = $(element).getStyle('display');
    if (display != 'none' && display != null) // Safari bug
      return {width: element.offsetWidth, height: element.offsetHeight};
    
    // All *Width and *Height properties give 0 on elements with display none,
    // so enable the element temporarily
    var els = element.style;
    var originalVisibility = els.visibility;
    var originalPosition = els.position;
    var originalDisplay = els.display;
    els.visibility = 'hidden';
    els.position = 'absolute';
    els.display = 'block';
    var originalWidth = element.clientWidth;
    var originalHeight = element.clientHeight;
    els.display = originalDisplay;
    els.position = originalPosition;
    els.visibility = originalVisibility;
    return {width: originalWidth, height: originalHeight};    
  },
  
  makePositioned: function(element) {
    element = $(element);
    var pos = Element.getStyle(element, 'position');
    if (pos == 'static' || !pos) {
      element._madePositioned = true;
      element.style.position = 'relative';
      // Opera returns the offset relative to the positioning context, when an
      // element is position relative but top and left have not been defined
      if (window.opera) {
        element.style.top = 0;
        element.style.left = 0;
      }  
    }
    return element;
  },

  undoPositioned: function(element) {
    element = $(element);
    if (element._madePositioned) {
      element._madePositioned = undefined;
      element.style.position =
        element.style.top =
        element.style.left =
        element.style.bottom =
        element.style.right = '';   
    }
    return element;
  },

  makeClipping: function(element) {
    element = $(element);
    if (element._overflow) return element;
    element._overflow = element.style.overflow || 'auto';
    if ((Element.getStyle(element, 'overflow') || 'visible') != 'hidden')
      element.style.overflow = 'hidden';
    return element;
  },

  undoClipping: function(element) {
    element = $(element);
    if (!element._overflow) return element;
    element.style.overflow = element._overflow == 'auto' ? '' : element._overflow;
    element._overflow = null;
    return element;
  }
};

Object.extend(Element.Methods, {childOf: Element.Methods.descendantOf});

Element._attributeTranslations = {};

Element._attributeTranslations.names = {
  colspan:   "colSpan",
  rowspan:   "rowSpan",
  valign:    "vAlign",
  datetime:  "dateTime",
  accesskey: "accessKey",
  tabindex:  "tabIndex",
  enctype:   "encType",
  maxlength: "maxLength",
  readonly:  "readOnly",
  longdesc:  "longDesc"
};

Element._attributeTranslations.values = {
  _getAttr: function(element, attribute) {
    return element.getAttribute(attribute, 2);
  },
  
  _flag: function(element, attribute) {
    return $(element).hasAttribute(attribute) ? attribute : null;
  },
  
  style: function(element) {
    return element.style.cssText.toLowerCase();
  },
  
  title: function(element) {
    var node = element.getAttributeNode('title');
    return node.specified ? node.nodeValue : null;
  }
};

Object.extend(Element._attributeTranslations.values, {
  href: Element._attributeTranslations.values._getAttr,
  src:  Element._attributeTranslations.values._getAttr,
  disabled: Element._attributeTranslations.values._flag,
  checked:  Element._attributeTranslations.values._flag,
  readonly: Element._attributeTranslations.values._flag,
  multiple: Element._attributeTranslations.values._flag
});

Element.Methods.Simulated = {
  hasAttribute: function(element, attribute) {
    var t = Element._attributeTranslations;
    attribute = t.names[attribute] || attribute;
    return $(element).getAttributeNode(attribute).specified;
  }
};

// IE is missing .innerHTML support for TABLE-related elements
if (document.all && !window.opera){
  Element.Methods.update = function(element, html) {
    element = $(element);
    html = typeof html == 'undefined' ? '' : html.toString();
    var tagName = element.tagName.toUpperCase();  
    if (['THEAD','TBODY','TR','TD'].include(tagName)) {
      var div = document.createElement('div');
      switch (tagName) {
        case 'THEAD':
        case 'TBODY':
          div.innerHTML = '<table><tbody>' +  html.stripScripts() + '</tbody></table>';
          depth = 2;
          break;
        case 'TR':
          div.innerHTML = '<table><tbody><tr>' +  html.stripScripts() + '</tr></tbody></table>';
          depth = 3;
          break;
        case 'TD':
          div.innerHTML = '<table><tbody><tr><td>' +  html.stripScripts() + '</td></tr></tbody></table>';
          depth = 4;
      }
      $A(element.childNodes).each(function(node){
        element.removeChild(node)
      });
      depth.times(function(){ div = div.firstChild });
  
      $A(div.childNodes).each(
        function(node){ element.appendChild(node) });
    } else {
      element.innerHTML = html.stripScripts();
    }
    setTimeout(function() {html.evalScripts()}, 10);
    return element;
  }
};

Object.extend(Element, Element.Methods);

var _nativeExtensions = false;

if(/Konqueror|Safari|KHTML/.test(navigator.userAgent))
  ['', 'Form', 'Input', 'TextArea', 'Select'].each(function(tag) {
    var className = 'HTML' + tag + 'Element';
    if(window[className]) return;
    var klass = window[className] = {};
    klass.prototype = document.createElement(tag ? tag.toLowerCase() : 'div').__proto__;
  });

Element.addMethods = function(methods) {
  Object.extend(Element.Methods, methods || {});
  
  function copy(methods, destination, onlyIfAbsent) {
    onlyIfAbsent = onlyIfAbsent || false;
    var cache = Element.extend.cache;
    for (var property in methods) {
      var value = methods[property];
      if (!onlyIfAbsent || !(property in destination))
        destination[property] = cache.findOrStore(value);
    }
  }
  
  if (typeof HTMLElement != 'undefined') {
    copy(Element.Methods, HTMLElement.prototype);
    copy(Element.Methods.Simulated, HTMLElement.prototype, true);
    copy(Form.Methods, HTMLFormElement.prototype);
    [HTMLInputElement, HTMLTextAreaElement, HTMLSelectElement].each(function(klass) {
      copy(Form.Element.Methods, klass.prototype);
    });
    _nativeExtensions = true;
  }
}

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.stripScripts();
    
    if (this.adjacency && this.element.insertAdjacentHTML) {
      try {
        this.element.insertAdjacentHTML(this.adjacency, this.content);
      } catch (e) {
        var tagName = this.element.tagName.toUpperCase();
        if (['TBODY', 'TR'].include(tagName)) {
          this.insertContent(this.contentFromAnonymousTable());
        } else {
          throw e;
        }
      }
    } else {
      this.range = this.element.ownerDocument.createRange();
      if (this.initializeRange) this.initializeRange();
      this.insertContent([this.range.createContextualFragment(this.content)]);
    }

    setTimeout(function() {content.evalScripts()}, 10);   
  },
  
  contentFromAnonymousTable: function() {
    var div = document.createElement('div');
    div.innerHTML = '<table><tbody>' + this.content + '</tbody></table>';
    return $A(div.childNodes[0].childNodes[0].childNodes);
  }
}

var Insertion = new Object();

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

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

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

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

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

Element.ClassNames = Class.create();
Element.ClassNames.prototype = {
  initialize: function(element) {
    this.element = $(element);
  },

  _each: function(iterator) {
    this.element.className.split(/\s+/).select(function(name) {
      return name.length > 0;
    })._each(iterator);
  },
  
  set: function(className) {
    this.element.className = className;
  },
  
  add: function(classNameToAdd) {
    if (this.include(classNameToAdd)) return;
    this.set($A(this).concat(classNameToAdd).join(' '));
  },
  
  remove: function(classNameToRemove) {
    if (!this.include(classNameToRemove)) return;
    this.set($A(this).without(classNameToRemove).join(' '));
  },
  
  toString: function() {
    return $A(this).join(' ');
  }
};

Object.extend(Element.ClassNames.prototype, Enumerable);