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, $(parentElement) || document,
      null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
    for (var i = 0, length = query.snapshotLength; i < length; i++)
      results.push(query.snapshotItem(i));
    return results;
  };
  document.getElementsByClassName = function(className, parentElement) {
    var q = ".//*[contains(concat(' ', @class, ' '), ' " + className + " ')]";
    return document._getElementsByXPath(q, parentElement);
  }
} else document.getElementsByClassName = function(className, parentElement) {
  var children = ($(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 = {};

Element.extend = function(element) {
  var F = Prototype.BrowserFeatures;
  if (!element || !element.tagName || element.nodeType == 3 || 
   element._extended || F.SpecificElementExtensions || element == window) 
    return element;

  var methods = {}, tagName = element.tagName, cache = Element.extend.cache, 
   T = Element.Methods.ByTag;

  // extend methods for all tags (Safari doesn't need this)
  if (!F.ElementExtensions) {
    Object.extend(methods, Element.Methods), 
    Object.extend(methods, Element.Methods.Simulated);      
  }

  // extend methods for specific tags
  if (T[tagName]) Object.extend(methods, T[tagName]);

  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.blank();
  },
  
  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);
    style = style == 'float' ? 'cssFloat' : style.camelize();
    var value = element.style[style];
    if (!value) {
      var css = document.defaultView.getComputedStyle(element, null);
      value = css ? css[style] : null;
    }
    if (style == 'opacity') return value ? parseFloat(value) : 1.0;
    return value == 'auto' ? null : value;
  },
  
  getOpacity: function(element) {
    return $(element).getStyle('opacity');
  },
  
  setStyle: function(element, styles, camelized) {
    element = $(element);
    var elementStyle = element.style;

    for (var property in styles)
      if (property == 'opacity') element.setOpacity(styles[property])
      else 
        elementStyle[(property == 'float' || property == 'cssFloat') ?
          (elementStyle.styleFloat === undefined ? 'cssFloat' : 'styleFloat') : 
          (camelized ? property : property.camelize())] = styles[property];

    return element;
  },
  
  setOpacity: function(element, value) {
    element = $(element);
    element.style.opacity = (value == 1 || value === '') ? '' : 
      (value < 0.00001) ? 0 : 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});

if (Prototype.Browser.Opera) { 
  Element.Methods._getStyle = Element.Methods.getStyle; 
  Element.Methods.getStyle = function(element, style) { 
    switch(style) { 
      case 'left': 
      case 'top': 
      case 'right': 
      case 'bottom': 
        if(Element._getStyle(element, 'position') == 'static') return null; 
      default: return Element._getStyle(element, style); 
    } 
  }; 
}
else if (Prototype.Browser.IE) {
  Element.Methods.getStyle = function(element, style) {
    element = $(element);
    style = (style == 'float' || style == 'cssFloat') ? 'styleFloat' : style.camelize();
    var value = element.style[style];
    if (!value && element.currentStyle) value = element.currentStyle[style];

    if (style == 'opacity') {
      if (value = (element.getStyle('filter') || '').match(/alpha\(opacity=(.*)\)/))
        if (value[1]) return parseFloat(value[1]) / 100;
      return 1.0;
    }

    if (value == 'auto') {
      if ((style == 'width' || style == 'height') && (element.getStyle('display') != 'none'))
        return element['offset'+style.capitalize()] + 'px';
      return null;
    }
    return value;
  };
  
  Element.Methods.setOpacity = function(element, value) {
    element = $(element);
    var filter = element.getStyle('filter'), style = element.style;
    if (value == 1 || value === '') {
      style.filter = filter.replace(/alpha\([^\)]*\)/gi,'');
      return element;
    } else if (value < 0.00001) value = 0;
    style.filter = filter.replace(/alpha\([^\)]*\)/gi, '') +
      'alpha(opacity=' + (value * 100) + ')';
    return element;   
  };

  // IE is missing .innerHTML support for TABLE-related elements
  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;
  }
}
else if (Prototype.Browser.Gecko) {
  Element.Methods.setOpacity = function(element, value) {
    element = $(element);
    element.style.opacity = (value == 1) ? 0.999999 : 
      (value === '') ? '' : (value < 0.00001) ? 0 : value;
    return element;
  };
}

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

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

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

Element.Methods.ByTag = {};

Object.extend(Element, Element.Methods);

if (!Prototype.BrowserFeatures.ElementExtensions && 
 document.createElement('div').__proto__) {
  window.HTMLElement = {};
  window.HTMLElement.prototype = document.createElement('div').__proto__;
  Prototype.BrowserFeatures.ElementExtensions = true;
}

Element.addMethods = function(methods) {
  var F = Prototype.BrowserFeatures, T = Element.Methods.ByTag;
  if (arguments.length == 2) {
    var tagName = methods;
    methods = arguments[1];
  }
  
  if (!tagName) Object.extend(Element.Methods, methods || {});  
  else {
    if (tagName.constructor == Array) tagName.each(extend);
    else extend(tagName);
  }
  
  function extend(tagName) {
    tagName = tagName.toUpperCase();
    if (!Element.Methods.ByTag[tagName])
      Element.Methods.ByTag[tagName] = {};
    Object.extend(Element.Methods.ByTag[tagName], 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);
    }
  }
  
  function findDOMClass(tagName) {
    var klass;
    var trans = {       
      "OPTGROUP": "OptGroup", "TEXTAREA": "TextArea", "P": "Paragraph", 
      "FIELDSET": "FieldSet", "UL": "UList", "OL": "OList", "DL": "DList",
      "DIR": "Directory", "H1": "Heading", "H2": "Heading", "H3": "Heading",
      "H4": "Heading", "H5": "Heading", "H6": "Heading", "Q": "Quote", 
      "INS": "Mod", "DEL": "Mod", "A": "Anchor", "IMG": "Image", "CAPTION": 
      "TableCaption", "COL": "TableCol", "COLGROUP": "TableCol", "THEAD": 
      "TableSection", "TFOOT": "TableSection", "TBODY": "TableSection", "TR":
      "TableRow", "TH": "TableCell", "TD": "TableCell", "FRAMESET": 
      "FrameSet", "IFRAME": "IFrame"
    };
    if (trans[tagName]) klass = 'HTML' + trans[tagName] + 'Element';
    if (window[klass]) return window[klass];
    klass = 'HTML' + tagName + 'Element';
    if (window[klass]) return window[klass];
    klass = 'HTML' + tagName.capitalize() + 'Element';
    if (window[klass]) return window[klass];
    
    window[klass] = {};
    window[klass].prototype = document.createElement(tagName).__proto__;
    return window[klass];
  }
  
  if (F.ElementExtensions) {
    copy(Element.Methods, HTMLElement.prototype);
    copy(Element.Methods.Simulated, HTMLElement.prototype, true);
  }
  
  if (F.SpecificElementExtensions) {
    for (var tag in Element.Methods.ByTag) {
      var klass = findDOMClass(tag);
      if (typeof klass == "undefined") continue;
      copy(T[tag], klass.prototype);
    }
  }  
};

var 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);