ment.offsetLeft || 0;

      // Safari fix
      if (element.offsetParent == document.body &&
        Element.getStyle(element, 'position') == 'absolute') break;

    } while (element = element.offsetParent);

    element = forElement;
    do {
      if (!Prototype.Browser.Opera || element.tagName == 'BODY') {
        valueT -= element.scrollTop  || 0;
        valueL -= element.scrollLeft || 0;
      }
    } while (element = element.parentNode);

    return Element._returnOffset(valueL, valueT);
  },

  clonePosition: function(element, source) {
    var options = Object.extend({
      setLeft:    true,
      setTop:     true,
      setWidth:   true,
      setHeight:  true,
      offsetTop:  0,
      offsetLeft: 0
    }, arguments[2] || { });

    // find page position of source
    source = $(source);
    var p = source.viewportOffset();

    // find coordinate system to use
    element = $(element);
    var delta = [0, 0];
    var parent = null;
    // delta [0,0] will do fine with position: fixed elements,
    // position:absolute needs offsetParent deltas
    if (Element.getStyle(element, 'position') == 'absolute') {
      parent = element.getOffsetParent();
      delta = parent.viewportOffset();
    }

    // correct by body offsets (fixes Safari)
    if (parent == document.body) {
      delta[0] -= document.body.offsetLeft;
      delta[1] -= document.body.offsetTop;
    }

    // set position
    if (options.setLeft)   element.style.left  = (p[0] - delta[0] + options.offsetLeft) + 'px';
    if (options.setTop)    element.style.top   = (p[1] - delta[1] + options.offsetTop) + 'px';
    if (options.setWidth)  element.style.width = source.offsetWidth + 'px';
    if (options.setHeight) element.style.height = source.offsetHeight + 'px';
    return element;
  }
};

Element.Methods.identify.counter = 1;

Object.extend(Element.Methods, {
  getElementsBySelector: Element.Methods.select,
  childElements: Element.Methods.immediateDescendants
});

Element._attributeTranslations = {
  write: {
    names: {
      className: 'class',
      htmlFor:   'for'
    },
    values: { }
  }
};

if (Prototype.Browser.Opera) {
  Element.Methods.getStyle = Element.Methods.getStyle.wrap(
    function(proceed, element, style) {
      switch (style) {
        case 'left': case 'top': case 'right': case 'bottom':
          if (proceed(element, 'position') === 'static') return null;
        case 'height': case 'width':
          // returns '0px' for hidden elements; we want it to return null
          if (!Element.visible(element)) return null;

          // returns the border-box dimensions rather than the content-box
          // dimensions, so we subtract padding and borders from the value
          var dim = parseInt(proceed(element, style), 10);

          if (dim !== element['offset' + style.capitalize()])
            return dim + 'px';

          var properties;
          if (style === 'height') {
            properties = ['border-top-width', 'padding-top',
             'padding-bottom', 'border-bottom-width'];
          }
          else {
            properties = ['border-left-width', 'padding-left',
             'padding-right', 'border-right-width'];
          }
          return properties.inject(dim, function(memo, property) {
            var val = proceed(element, property);
            return val === null ? memo : memo - parseInt(val, 10);
          }) + 'px';
        default: return proceed(element, style);
      }
    }
  );

  Element.Methods.readAttribute = Element.Methods.readAttribute.wrap(
    function(proceed, element, attribute) {
      if (attribute === 'title') return element.title;
      return proceed(element, attribute);
    }
  );
}

else if (Prototype.Browser.IE) {
  // IE doesn't report offsets correctly for static elements, so we change them
  // to "relative" to get the values, then change them back.
  Element.Methods.getOffsetParent = Element.Methods.getOffsetParent.wrap(
    function(proceed, element) {
      element = $(element);
      var position = element.getStyle('position');
      if (position !== 'static') return proceed(element);
      element.setStyle({ position: 'relative' });
      var value = proceed(element);
      element.setStyle({ position: position });
      return value;
    }
  );

  $w('positionedOffset viewportOffset').each(function(method) {
    Element.Methods[method] = Element.Methods[method].wrap(
      function(proceed, element) {
        element = $(element);
        var position = element.getStyle('position');
        if (position !== 'static') return proceed(element);
        // Trigger hasLayout on the offset parent so that IE6 reports
        // accurate offsetTop and offsetLeft values for position: fixed.
        var offsetParent = element.getOffsetParent();
        if (offsetParent && offsetParent.getStyle('position') === 'fixed')
          offsetParent.setStyle({ zoom: 1 });
        element.setStyle({ position: 'relative' });
        var value = proceed(element);
        element.setStyle({ position: position });
        return value;
      }
    );
  });

  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) {
    function stripAlpha(filter){
      return filter.replace(/alpha\([^\)]*\)/gi,'');
    }
    element = $(element);
    var currentStyle = element.currentStyle;
    if ((currentStyle && !currentStyle.hasLayout) ||
      (!currentStyle && element.style.zoom == 'normal'))
        element.style.zoom = 1;

    var filter = element.getStyle('filter'), style = element.style;
    if (value == 1 || value === '') {
      (filter = stripAlpha(filter)) ?
        style.filter = filter : style.removeAttribute('filter');
      return element;
    } else if (value < 0.00001) value = 0;
    style.filter = stripAlpha(filter) +
      'alpha(opacity=' + (value * 100) + ')';
    return element;
  };

  Element._attributeTranslations = {
    read: {
      names: {
        'class': 'className',
        'for':   'htmlFor'
      },
      values: {
        _getAttr: function(element, attribute) {
          return element.getAttribute(attribute, 2);
        },
        _getAttrNode: function(element, attribute) {
          var node = element.getAttributeNode(attribute);
          return node ? node.value : "";
        },
        _getEv: function(element, attribute) {
          attribute = element.getAttribute(attribute);
          return attribute ? attribute.toString().slice(23, -2) : null;
        },
        _flag: function(element, attribute) {
          return $(element).hasAttribute(attribute) ? attribute : null;
        },
        style: function(element) {
          return element.style.cssText.toLowerCase();
        },
        title: function(element) {
          return element.title;
        }
      }
    }
  };

  Element._attributeTranslations.write = {
    names: Object.extend({
      cellpadding: 'cellPadding',
      cellspacing: 'cellSpacing'
    }, Element._attributeTranslations.read.names),
    values: {
      checked: function(element, value) {
        element.checked = !!value;
      },

      style: function(element, value) {
        element.style.cssText = value ? value : '';
      }
    }
  };

  Element._attributeTranslations.has = {};

  $w('colSpan rowSpan vAlign dateTime accessKey tabIndex ' +
      'encType maxLength readOnly longDesc').each(function(attr) {
    Element._attributeTranslations.write.names[attr.toLowerCase()] = attr;
    Element._attributeTranslations.has[attr.toLowerCase()] = attr;
  });

  (function(v) {
    Object.extend(v, {
      href:        v._getAttr,
      src:         v._getAttr,
      type:        v._getAttr,
      action:      v._getAttrNode,
      disabled:    v._flag,
      checked:     v._flag,
      readonly:    v._flag,
      multiple:    v._flag,
      onload:      v._getEv,
      onunload:    v._getEv,
      onclick:     v._getEv,
      ondblclick:  v._getEv,
      onmousedown: v._getEv,
      onmouseup:   v._getEv,
      onmouseover: v._getEv,
      onmousemove: v._getEv,
      onmouseout:  v._getEv,
      onfocus:     v._getEv,
      onblur:      v._getEv,
      onkeypress:  v._getEv,
      onkeydown:   v._getEv,
      onkeyup:     v._getEv,
      onsubmit:    v._getEv,
      onreset:     v._getEv,
      onselect:    v._getEv,
      onchange:    v._getEv
    });
  })(Element._attributeTranslations.read.values);
}

else if (Prototype.Browser.Gecko && /rv:1\.8\.0/.test(navigator.userAgent)) {
  Element.Methods.setOpacity = function(element, value) {
    element = $(element);
    element.style.opacity = (value == 1) ? 0.999999 :
      (value === '') ? '' : (value < 0.00001) ? 0 : value;
    return element;
  };
}

else if (Prototype.Browser.WebKit) {
  Element.Methods.setOpacity = function(element, value) {
    element = $(element);
    element.style.opacity = (value == 1 || value === '') ? '' :
      (value < 0.00001) ? 0 : value;

    if (value == 1)
      if(element.tagName == 'IMG' && element.width) {
        element.width++; element.width--;
      } else try {
        var n = document.createTextNode(' ');
        element.appendChild(n);
        element.removeChild(n);
      } catch (e) { }

    return element;
  };

  // Safari returns margins on body which is incorrect if the child is absolutely
  // positioned.  For performance reasons, redefine Element#cumulativeOffset for
  // KHTML/WebKit only.
  Element.Methods.cumulativeOffset = function(element) {
    var valueT = 0, valueL = 0;
    do {
      valueT += element.offsetTop  || 0;
      valueL += element.offsetLeft || 0;
      if (element.offsetParent == document.body)
        if (Element.getStyle(element, 'position') == 'absolute') break;

      element = element.offsetParent;
    } while (element);

    return Element._returnOffset(valueL, valueT);
  };
}

if (Prototype.Browser.IE || Prototype.Browser.Opera) {
  // IE and Opera are missing .innerHTML support for TABLE-related and SELECT elements
  Element.Methods.update = function(element, content) {
    element = $(element);

    if (content && content.toElement) content = content.toElement();
    if (Object.isElement(content)) return element.update().insert(content);

    content = Object.toHTML(content);
    var tagName = element.tagName.toUpperCase();

    if (tagName in Element._insertionTranslations.tags) {
      $A(element.childNodes).each(function(node) { element.removeChild(node) });
      Element._getContentFromAnonymousElement(tagName, content.stripScripts())
        .each(function(node) { element.appendChild(node) });
    }
    else element.innerHTML = content.stripScripts();

    content.evalScripts.bind(content).defer();
    return element;
  };
}

if ('outerHTML' in document.createElement('div')) {
  Element.Methods.replace = function(element, content) {
    element = $(element);

    if (content && content.toElement) content = content.toElement();
    if (Object.isElement(content)) {
      element.parentNode.replaceChild(content, element);
      return element;
    }

    content = Object.toHTML(content);
    var parent = element.parentNode, tagName = parent.tagName.toUpperCase();

    if (Element._insertionTranslations.tags[tagName]) {
      var nextSibling = element.next();
      var fragments = Element._getContentFromAnonymousElement(tagName, content.stripScripts());
      parent.removeChild(element);
      if (nextSibling)
        fragments.each(function(node) { parent.insertBefore(node, nextSibling) });
      else
        fragments.each(function(node) { parent.appendChild(node) });
    }
    else element.outerHTML = content.stripScripts();

    content.evalScripts.bind(content).defer();
    return element;
  };
}

Element._returnOffset = function(l, t) {
  var result = [l, t];
  result.left = l;
  result.top = t;
  return result;
};

Element._getContentFromAnonymousElement = function(tagName, html) {
  var div = new Element('div'), t = Element._insertionTranslations.tags[tagName];
  if (t) {
    div.innerHTML = t[0] + html + t[1];
    t[2].times(function() { div = div.firstChild });
  } else div.innerHTML = html;
  return $A(div.childNodes);
};

Element._insertionTranslations = {
  before: function(element, node) {
    element.parentNode.insertBefore(node, element);
  },
  top: function(element, node) {
    element.insertBefore(node, element.firstChild);
  },
  bottom: function(element, node) {
    element.appendChild(node);
  },
  after: function(element, node) {
    element.parentNode.insertBefore(node, element.nextSibling);
  },
  tags: {
    TABLE:  ['<table>',                '</table>',                   1],
    TBODY:  ['<table><tbody>',         '</tbody></table>',           2],
    TR:     ['<table><tbody><tr>',     '</tr></tbody></table>',      3],
    TD:     ['<table><tbody><tr><td>', '</td></tr></tbody></table>', 4],
    SELECT: ['<select>',               '</select>',                  1]
  }
};

(function() {
  Object.extend(this.tags, {
    THEAD: this.tags.TBODY,
    TFOOT: this.tags.TBODY,
    TH:    this.tags.TD
  });
}).call(Element._insertionTranslations);

Element.Methods.Simulated = {
  hasAttribute: function(element, attribute) {
    attribute = Element._attributeTranslations.has[attribute] || attribute;
    var 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.extend = (function() {
  if (Prototype.BrowserFeatures.SpecificElementExtensions)
    return Prototype.K;

  var Methods = { }, ByTag = Element.Methods.ByTag;

  var extend = Object.extend(function(element) {
    if (!element || element._extendedByPrototype ||
        element.nodeType != 1 || element == window) return element;

    var methods = Object.clone(Methods),
      tagName = element.tagName, property, value;

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

    for (property in methods) {
      value = methods[property];
      if (Object.isFunction(value) && !(property in element))
        element[property] = value.methodize();
    }

    element._extendedByPrototype = Prototype.emptyFunction;
    return element;

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

  extend.refresh();
  return extend;
})();

Element.hasAttribute = function(element, attribute) {
  if (element.hasAttribute) return element.hasAttribute(attribute);
  return Element.Methods.Simulated.hasAttribute(element, attribute);
};

Element.addMethods = function(methods) {
  var F = Prototype.BrowserFeatures, T = Element.Methods.ByTag;

  if (!methods) {
    Object.extend(Form, Form.Methods);
    Object.extend(Form.Element, Form.Element.Methods);
    Object.extend(Element.Methods.ByTag, {
      "FORM":     Object.clone(Form.Methods),
      "INPUT":    Object.clone(Form.Element.Methods),
      "SELECT":   Object.clone(Form.Element.Methods),
      "TEXTAREA": Object.clone(Form.Element.Methods)
    });
  }

  if (arguments.length == 2) {
    var tagName = methods;
    methods = arguments[1];
  }

  if (!tagName) Object.extend(Element.Methods, methods || { });
  else {
    if (Object.isArray(tagName)) 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;
    for (var property in methods) {
      var value = methods[property];
      if (!Object.isFunction(value)) continue;
      if (!onlyIfAbsent || !(property in destination))
        destination[property] = value.methodize();
    }
  }

  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 (Object.isUndefined(klass)) continue;
      copy(T[tag], klass.prototype);
    }
  }

  Object.extend(Element, Element.Methods);
  delete Element.ByTag;

  if (Element.extend.refresh) Element.extend.refresh();
  Element.cache = { };
};

document.viewport = {
  getDimensions: function() {
    var dimensions = { };
    var B = Prototype.Browser;
    $w('width height').each(function(d) {
      var D = d.capitalize();
      dimensions[d] = (B.WebKit && !document.evaluate) ? self['inner' + D] :
        (B.Opera) ? document.body['client' + D] : document.documentElement['client' + D];
    });
    return dimensions;
  },

  getWidth: function() {
    return this.getDimensions().width;
  },

  getHeight: function() {
    return this.getDimensions().height;
  },

  getScrollOffsets: function() {
    return Element._returnOffset(
      window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft,
      window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop);
  }
};
/* Portions of the Selector class are derived from Jack Slocum’s DomQuery,
 * part of YUI-Ext version 0.40, distributed under the terms of an MIT-style
 * license.  Please see http://www.yui-ext.com/ for more information. */

var Selector = Class.create({
  initialize: function(expression) {
    this.expression = expression.strip();
    this.compileMatcher();
  },

  shouldUseXPath: function() {
    if (!Prototype.BrowserFeatures.XPath) return false;

    var e = this.expression;

    // Safari 3 chokes on :*-of-type and :empty
    if (Prototype.Browser.WebKit &&
     (e.include("-of-type") || e.include(":empty")))
      return false;

    // XPath can't do namespaced attributes, nor can it read
    // the "checked" property from DOM nodes
    if ((/(\[[\w-]*?:|:checked)/).test(this.expression))
      return false;

    return true;
  },

  compileMatcher: function() {
    if (this.shouldUseXPath())
      return this.compileXPathMatcher();

    var e = this.expression, ps = Selector.patterns, h = Selector.handlers,
        c = Selector.criteria, le, p, m;

    if (Selector._cache[e]) {
      this.matcher = Selector._cache[e];
      return;
    }

    this.matcher = ["this.matcher = function(root) {",
                    "var r = root, h = Selector.handlers, c = false, n;"];

    while (e && le != e && (/\S/).test(e)) {
      le = e;
      for (var i in ps) {
        p = ps[i];
        if (m = e.match(p)) {
          this.matcher.push(Object.isFunction(c[i]) ? c[i](m) :
    	      new Template(c[i]).evaluate(m));
          e = e.replace(m[0], '');
          break;
        }
      }
    }

    this.matcher.push("return h.unique(n);\n}");
    eval(this.matcher.join('\n'));
    Selector._cache[this.expression] = this.matcher;
  },

  compileXPathMatcher: function() {
    var e = this.expression, ps = Selector.patterns,
        x = Selector.xpath, le, m;

    if (Selector._cache[e]) {
      this.xpath = Selector._cache[e]; return;
    }

    this.matcher = ['.//*'];
    while (e && le != e && (/\S/).test(e)) {
      le = e;
      for (var i in ps) {
        if (m = e.match(ps[i])) {
          this.matcher.push(Object.isFunction(x[i]) ? x[i](m) :
            new Template(x[i]).evaluate(m));
          e = e.replace(m[0], '');
          break;
        }
      }
    }

    this.xpath = this.matcher.join('');
    Selector._cache[this.expression] = this.xpath;
  },

  findElements: function(root) {
    root = root || document;
    if (this.xpath) return document._getElementsByXPath(this.xpath, root);
    return this.matcher(root);
  },

  match: function(element) {
    this.tokens = [];

    var e = this.expression, ps = Selector.patterns, as = Selector.assertions;
    var le, p, m;

    while (e && le !== e && (/\S/).test(e)) {
      le = e;
      for (var i in ps) {
        p = ps[i];
        if (m = e.match(p)) {
          // use the Selector.assertions methods unless the selector
          // is too complex.
          if (as[i]) {
            this.tokens.push([i, Object.clone(m)]);
            e = e.replace(m[0], '');
          } else {
            // reluctantly do a document-wide search
            // and look for a match in the array
            return this.findElements(document).include(element);
          }
        }
      }
    }

    var match = true, name, matches;
    for (var i = 0, token; token = this.tokens[i]; i++) {
      name = token[0], matches = token[1];
      if (!Selector.assertions[name](element, matches)) {
        match = false; break;
      }
    }

    return match;
  },

  toString: function() {
    return this.expression;
  },

  inspect: function() {
    return "#<Selector:" + this.expression.inspect() + ">";
  }
});

Object.extend(Selector, {
  _cache: { },

  xpath: {
    descendant:   "//*",
    child:        "/*",
    adjacent:     "/following-sibling::*[1]",
    laterSibling: '/following-sibling::*',
    tagName:      function(m) {
      if (m[1] == '*') return '';
      return "[local-name()='" + m[1].toLowerCase() +
             "' or local-name()='" + m[1].toUpperCase() + "']";
    },
    className:    "[contains(concat(' ', @class, ' '), ' #{1} ')]",
    id:           "[@id='#{1}']",
    attrPresence: function(m) {
      m[1] = m[1].toLowerCase();
      return new Template("[@#{1}]").evaluate(m);
    },
    attr: function(m) {
      m[1] = m[1].toLowerCase();
      m[3] = m[5] || m[6];
      return new Template(Selector.xpath.operators[m[2]]).evaluate(m);
    },
    pseudo: function(m) {
      var h = Selector.xpath.pseudos[m[1]];
      if (!h) return '';
      if (Object.isFunction(h)) return h(m);
      return new Template(Selector.xpath.pseudos[m[1]]).evaluate(m);
    },
    operators: {
      '=':  "[@#{1}='#{3}']",
      '!=': "[@#{1}!='#{3}']",
      '^=': "[starts-with(@#{1}, '#{3}')]",
      '$=': "[substring(@#{1}, (string-length(@#{1}) - string-length('#{3}') + 1))='#{3}']",
      '*=': "[contains(@#{1}, '#{3}')]",
      '~=': "[contains(concat(' ', @#{1}, ' '), ' #{3} ')]",
      '|=': "[contains(concat('-', @#{1}, '-'), '-#{3}-')]"
    },
    pseudos: {
      'first-child': '[not(preceding-sibling::*)]',
      'last-child':  '[not(following-sibling::*)]',
      'only-child':  '[not(preceding-sibling::* or following-sibling::*)]',
      'empty':       "[count(*) = 0 and (count(text()) = 0 or translate(text(), ' \t\r\n', '') = '')]",
      'checked':     "[@checked]",
      'disabled':    "[@disabled]",
      'enabled':     "[not(@disabled)]",
      'not': function(m) {
        var e = m[6], p = Selector.patterns,
            x = Selector.xpath, le, v;

        var exclusion = [];
        while (e && le != e && (/\S/).test(e)) {
          le = e;
          for (var i in p) {
            if (m = e.match(p[i])) {
              v = Object.isFunction(x[i]) ? x[i](m) : new Template(x[i]).evaluate(m);
              exclusion.push("(" + v.substring(1, v.length - 1) + ")");
              e = e.replace(m[0], '');
              break;
            }
          }
        }
        return "[not(" + exclusion.join(" and ") + ")]";
      },
      'nth-child':      function(m) {
        return Selector.xpath.pseudos.nth("(count(./preceding-sibling::*) + 1) ", m);
      },
      'nth-last-child': function(m) {
        return Selector.xpath.pseudos.nth("(count(./following-sibling::*) + 1) ", m);
      },
      'nth-of-type':    function(m) {
        return Selector.xpath.pseudos.nth("position() ", m);
      },
      'nth-last-of-type': function(m) {
        return Selector.xpath.pseudos.nth("(last() + 1 - position()) ", m);
      },
      'first-of-type':  function(m) {
        m[6] = "1"; return Selector.xpath.pseudos['nth-of-type'](m);
      },
      'last-of-type':   function(m) {
        m[6] = "1"; return Selector.xpath.pseudos['nth-last-of-type'](m);
      },
      'only-of-type':   function(m) {
        var p = Selector.xpath.pseudos; return p['first-of-type'](m) + p['last-of-type'](m);
      },
      nth: function(fragment, m) {
        var mm, formula = m[6], predicate;
        if (formula == 'even') formula = '2n+0';
        if (formula == 'odd')  formula = '2n+1';
        if (mm = formula.match(/^(\d+)$/)) // digit only
          return '[' + fragment + "= " + mm[1] + ']';
        if (mm = formula.match(/^(-?\d*)?n(([+-])(\d+))?/)) { // an+b
          if (mm[1] == "-") mm[1] = -1;
          var a = mm[1] ? Number(mm[1]) : 1;
          var b = mm[2] ? Number(mm[2]) : 0;
          predicate = "[((#{fragment} - #{b}) mod #{a} = 0) and " +
          "((#{fragment} - #{b}) div #{a} >= 0)]";
          return new Template(predicate).evaluate({
            fragment: fragment, a: a, b: b });
        }
      }
    }
  },

  criteria: {
    tagName:      'n = h.tagName(n, r, "#{1}", c);      c = false;',
    className:    'n = h.className(n, r, "#{1}", c);    c = false;',
    id:           'n = h.id(n, r, "#{1}", c);           c = false;',
    attrPresence: 'n = h.attrPresence(n, r, "#{1}", c); c = false;',
    attr: function(m) {
      m[3] = (m[5] || m[6]);
      return new Template('n = h.attr(n, r, "#{1}", "#{3}", "#{2}", c); c = false;').evaluate(m);
    },
    pseudo: function(m) {
      if (m[6]) m[6] = m[6].replace(/"/g, '\\"');
      return new Template('n = h.pseudo(n, "#{1}", "#{6}", r, c); c = false;').evaluate(m);
    },
    descendant:   'c = "descendant";',
    child:        'c = "child";',
    adjacent:     'c = "adjacent";',
    laterSibling: 'c = "laterSibling";'
  },

  patterns: {
    // combinators must be listed first
    // (and descendant needs to be last combinator)
    laterSibling: /^\s*~\s*/,
    child:        /^\s*>\s*/,
    adjacent:     /^\s*\+\s*/,
    descendant:   /^\s/,

    // selectors follow
    tagName:      /^\s*(\*|[\w\-]+)(\b|$)?/,
    id:           /^#([\w\-\*]+)(\b|$)/,
    className:    /^\.([\w\-\*]+)(\b|$)/,
    pseudo:
/^:((first|last|nth|nth-last|only)(-child|-of-type)|empty|checked|(en|dis)abled|not)(\((.*?)\))?(\b|$|(?=\s|[:+~>]))/,
    attrPresence: /^\[([\w]+)\]/,
    attr:         /\[((?:[\w-]*:)?[\w-]+)\s*(?:([!^$*~|]?=)\s*((['"])([^\4]*?)\4|([^'"][^\]]*?)))?\]/
  },

  // for Selector.match and Element#match
  assertions: {
    tagName: function(element, matches) {
      return matches[1].toUpperCase() == element.tagName.toUpperCase();
    },

    className: function(element, matches) {
      return Element.hasClassName(element, matches[1]);
    },

    id: function(element, matches) {
      return element.id === matches[1];
    },

    attrPresence: function(element, matches) {
      return Element.hasAttribute(element, matches[1]);
    },

    attr: function(element, matches) {
      var nodeValue = Element.readAttribute(element, matches[1]);
      return nodeValue && Selector.operators[matches[2]](nodeValue, matches[5] || matches[6]);
    }
  },

  handlers: {
    // UTILITY FUNCTIONS
    // joins two collections
    concat: function(a, b) {
      for (var i = 0, node; node = b[i]; i++)
        a.push(node);
      return a;
    },

    // marks an array of nodes for counting
    mark: function(nodes) {
      var _true = Prototype.emptyFunction;
      for (var i = 0, node; node = nodes[i]; i++)
        node._countedByPrototype = _true;
      return nodes;
    },

    unmark: function(nodes) {
      for (var i = 0, node; node = nodes[i]; i++)
        node._countedByPrototype = undefined;
      return nodes;
    },

    // mark each child node with its position (for nth calls)
    // "ofType" flag indicates whether we're indexing for nth-of-type
    // rather than nth-child
    index: function(parentNode, reverse, ofType) {
      parentNode._countedByPrototype = Prototype.emptyFunction;
      if (reverse) {
        for (var nodes = parentNode.childNodes, i = nodes.length - 1, j = 1; i >= 0; i--) {
          var node = nodes[i];
          if (node.nodeType == 1 && (!ofType || node._countedByPrototype)) node.nodeIndex = j++;
        }
      } else {
        for (var i = 0, j = 1, nodes = parentNode.childNodes; node = nodes[i]; i++)
          if (node.nodeType == 1 && (!ofType || node._countedByPrototype)) node.nodeIndex = j++;
      }
    },

    // filters out duplicates and extends all nodes
    unique: function(nodes) {
      if (nodes.length == 0) return nodes;
      var results = [], n;
      for (var i = 0, l = nodes.length; i < l; i++)
        if (!(n = nodes[i])._countedByPrototype) {
          n._countedByPrototype = Prototype.emptyFunction;
          results.push(Element.extend(n));
        }
      return Selector.handlers.unmark(results);
    },

    // COMBINATOR FUNCTIONS
    descendant: function(nodes) {
      var h = Selector.handlers;
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        h.concat(results, node.getElementsByTagName('*'));
      return results;
    },

    child: function(nodes) {
      var h = Selector.handlers;
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        for (var j = 0, child; child = node.childNodes[j]; j++)
          if (child.nodeType == 1 && child.tagName != '!') results.push(child);
      }
      return results;
    },

    adjacent: function(nodes) {
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        var next = this.nextElementSibling(node);
        if (next) results.push(next);
      }
      return results;
    },

    laterSibling: function(nodes) {
      var h = Selector.handlers;
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        h.concat(results, Element.nextSiblings(node));
      return results;
    },

    nextElementSibling: function(node) {
      while (node = node.nextSibling)
	      if (node.nodeType == 1) return node;
      return null;
    },

    previousElementSibling: function(node) {
      while (node = node.previousSibling)
        if (node.nodeType == 1) return node;
      return null;
    },

    // TOKEN FUNCTIONS
    tagName: function(nodes, root, tagName, combinator) {
      var uTagName = tagName.toUpperCase();
      var results = [], h = Selector.handlers;
      if (nodes) {
        if (combinator) {
          // fastlane for ordinary descendant combinators
          if (combinator == "descendant") {
            for (var i = 0, node; node = nodes[i]; i++)
              h.concat(results, node.getElementsByTagName(tagName));
            return results;
          } else nodes = this[combinator](nodes);
          if (tagName == "*") return nodes;
        }
        for (var i = 0, node; node = nodes[i]; i++)
          if (node.tagName.toUpperCase() === uTagName) results.push(node);
        return results;
      } else return root.getElementsByTagName(tagName);
    },

    id: function(nodes, root, id, combinator) {
      var targetNode = $(id), h = Selector.handlers;
      if (!targetNode) return [];
      if (!nodes && root == document) return [targetNode];
      if (nodes) {
        if (combinator) {
          if (combinator == 'child') {
            for (var i = 0, node; node = nodes[i]; i++)
              if (targetNode.parentNode == node) return [targetNode];
          } else if (combinator == 'descendant') {
            for (var i = 0, node; node = nodes[i]; i++)
              if (Element.descendantOf(targetNode, node)) return [targetNode];
          } else if (combinator == 'adjacent') {
            for (var i = 0, node; node = nodes[i]; i++)
              if (Selector.handlers.previousElementSibling(targetNode) == node)
                return [targetNode];
          } else nodes = h[combinator](nodes);
        }
        for (var i = 0, node; node = nodes[i]; i++)
          if (node == targetNode) return [targetNode];
        return [];
      }
      return (targetNode && Element.descendantOf(targetNode, root)) ? [targetNode] : [];
    },

    className: function(nodes, root, className, combinator) {
      if (nodes && combinator) nodes = this[combinator](nodes);
      return Selector.handlers.byClassName(nodes, root, className);
    },

    byClassName: function(nodes, root, className) {
      if (!nodes) nodes = Selector.handlers.descendant([root]);
      var needle = ' ' + className + ' ';
      for (var i = 0, results = [], node, nodeClassName; node = nodes[i]; i++) {
        nodeClassName = node.className;
        if (nodeClassName.length == 0) continue;
        if (nodeClassName == className || (' ' + nodeClassName + ' ').include(needle))
          results.push(node);
      }
      return results;
    },

    attrPresence: function(nodes, root, attr, combinator) {
      if (!nodes) nodes = root.getElementsByTagName("*");
      if (nodes && combinator) nodes = this[combinator](nodes);
      var results = [];
      for (var i = 0, node; node = nodes[i]; i++)
        if (Element.hasAttribute(node, attr)) results.push(node);
      return results;
    },

    attr: function(nodes, root, attr, value, operator, combinator) {
      if (!nodes) nodes = root.getElementsByTagName("*");
      if (nodes && combinator) nodes = this[combinator](nodes);
      var handler = Selector.operators[operator], results = [];
      for (var i = 0, node; node = nodes[i]; i++) {
        var nodeValue = Element.readAttribute(node, attr);
        if (nodeValue === null) continue;
        if (handler(nodeValue, value)) results.push(node);
      }
      return results;
    },

    pseudo: function(nodes, name, value, root, combinator) {
      if (nodes && combinator) nodes = this[combinator](nodes);
      if (!nodes) nodes = root.getElementsByTagName("*");
      return Selector.pseudos[name](nodes, value, root);
    }
  },

  pseudos: {
    'first-child': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        if (Selector.handlers.previousElementSibling(node)) continue;
          results.push(node);
      }
      return results;
    },
    'last-child': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        if (Selector.handlers.nextElementSibling(node)) continue;
          results.push(node);
      }
      return results;
    },
    'only-child': function(nodes, value, root) {
      var h = Selector.handlers;
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (!h.previousElementSibling(node) && !h.nextElementSibling(node))
          results.push(node);
      return results;
    },
    'nth-child':        function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, formula, root);
    },
    'nth-last-child':   function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, formula, root, true);
    },
    'nth-of-type':      function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, formula, root, false, true);
    },
    'nth-last-of-type': function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, formula, root, true, true);
    },
    'first-of-type':    function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, "1", root, false, true);
    },
    'last-of-type':     function(nodes, formula, root) {
      return Selector.pseudos.nth(nodes, "1", root, true, true);
    },
    'only-of-type':     function(nodes, formula, root) {
      var p = Selector.pseudos;
      return p['last-of-type'](p['first-of-type'](nodes, formula, root), formula, root);
    },

    // handles the an+b logic
    getIndices: function(a, b, total) {
      if (a == 0) return b > 0 ? [b] : [];
      return $R(1, total).inject([], function(memo, i) {
        if (0 == (i - b) % a && (i - b) / a >= 0) memo.push(i);
        return memo;
      });
    },

    // handles nth(-last)-child, nth(-last)-of-type, and (first|last)-of-type
    nth: function(nodes, formula, root, reverse, ofType) {
      if (nodes.length == 0) return [];
      if (formula == 'even') formula = '2n+0';
      if (formula == 'odd')  formula = '2n+1';
      var h = Selector.handlers, results = [], indexed = [], m;
      h.mark(nodes);
      for (var i = 0, node; node = nodes[i]; i++) {
        if (!node.parentNode._countedByPrototype) {
          h.index(node.parentNode, reverse, ofType);
          indexed.push(node.parentNode);
        }
      }
      if (formula.match(/^\d+$/)) { // just a number
        formula = Number(formula);
        for (var i = 0, node; node = nodes[i]; i++)
          if (node.nodeIndex == formula) results.push(node);
      } else if (m = formula.match(/^(-?\d*)?n(([+-])(\d+))?/)) { // an+b
        if (m[1] == "-") m[1] = -1;
        var a = m[1] ? Number(m[1]) : 1;
        var b = m[2] ? Number(m[2]) : 0;
        var indices = Selector.pseudos.getIndices(a, b, nodes.length);
        for (var i = 0, node, l = indices.length; node = nodes[i]; i++) {
          for (var j = 0; j < l; j++)
            if (node.nodeIndex == indices[j]) results.push(node);
        }
      }
      h.unmark(nodes);
      h.unmark(indexed);
      return results;
    },

    'empty': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++) {
        // IE treats comments as element nodes
        if (node.tagName == '!' || (node.firstChild && !node.innerHTML.match(/^\s*$/))) continue;
        results.push(node);
      }
      return results;
    },

    'not': function(nodes, selector, root) {
      var h = Selector.handlers, selectorType, m;
      var exclusions = new Selector(selector).findElements(root);
      h.mark(exclusions);
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (!node._countedByPrototype) results.push(node);
      h.unmark(exclusions);
      return results;
    },

    'enabled': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (!node.disabled) results.push(node);
      return results;
    },

    'disabled': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (node.disabled) results.push(node);
      return results;
    },

    'checked': function(nodes, value, root) {
      for (var i = 0, results = [], node; node = nodes[i]; i++)
        if (node.checked) results.push(node);
      return results;
    }
  },

  operators: {
    '=':  function(nv, v) { return nv == v; },
    '!=': function(nv, v) { return nv != v; },
    '^=': function(nv, v) { return nv.startsWith(v); },
    '$=': function(nv, v) { return nv.endsWith(v); },
    '*=': function(nv, v) { return nv.include(v); },
    '~=': function(nv, v) { return (' ' + nv + ' ').include(' ' + v + ' '); },
    '|=': function(nv, v) { return ('-' + nv.toUpperCase() + '-').include('-' + v.toUpperCase() + '-'); }
  },

  split: function(expression) {
    var expressions = [];
    expression.scan(/(([\w#:.~>+()\s-]+|\*|\[.*?\])+)\s*(,|$)/, function(m) {
      expressions.push(m[1].strip());
    });
    return expressions;
  },

  matchElements: function(elements, expression) {
    var matches = $$(expression), h = Selector.handlers;
    h.mark(matches);
    for (var i = 0, results = [], element; element = elements[i]; i++)
      if (element._countedByPrototype) results.push(element);
    h.unmark(matches);
    return results;
  },

  findElement: function(elements, expression, index) {
    if (Object.isNumber(expression)) {
      index = expression; expression = false;
    }
    return Selector.matchElements(elements, expression || '*')[index || 0];
  },

  findChildElements: function(element, expressions) {
    expressions = Selector.split(expressions.join(','));
    var results = [], h = Selector.handlers;
    for (var i = 0, l = expressions.length, selector; i < l; i++) {
      selector = new Selector(expressions[i].strip());
      h.concat(results, selector.findElements(element));
    }
    return (l > 1) ? h.unique(results) : results;
  }
});

if (Prototype.Browser.IE) {
  Object.extend(Selector.handlers, {
    // IE returns comment nodes on getElementsByTagName("*").
    // Filter them out.
    concat: function(a, b) {
      for (var i = 0, node; node = b[i]; i++)
        if (node.tagName !== "!") a.push(node);
      return a;
    },

    // IE improperly serializes _countedByPrototype in (inner|outer)HTML.
    unmark: function(nodes) {
      for (var i = 0, node; node = nodes[i]; i++)
        node.removeAttribute('_countedByPrototype');
      return nodes;
    }
  });
}

function $$() {
  return Selector.findChildElements(document, $A(arguments));
}
var Form = {
  reset: function(form) {
    $(form).reset();
    return form;
  },

  serializeElements: function(elements, options) {
    if (typeof options != 'object') options = { hash: !!options };
    else if (Object.isUndefined(options.hash)) options.hash = true;
    var key, value, submitted = false, submit = options.submit;

    var data = elements.inject({ }, function(result, element) {
      if (!element.disabled && element.name) {
        key = element.name; value = $(element).getValue();
        if (value != null && (element.type != 'submit' || (!submitted &&
            submit !== false && (!submit || key == submit) && (submitted = true)))) {
          if (key in result) {
            // a key is already present; construct an array of values
            if (!Object.isArray(result[key])) result[key] = [result[key]];
            result[key].push(value);
          }
          else result[key] = value;
        }
      }
      return result;
    });

    return options.hash ? data : Object.toQueryString(data);
  }
};

Form.Methods = {
  serialize: function(form, options) {
    return Form.serializeElements(Form.getElements(form), options);
  },

  getElements: function(form) {
    return $A($(form).getElementsByTagName('*')).inject([],
      function(elements, child) {
        if (Form.Element.Serializers[child.tagName.toLowerCase()])
          elements.push(Element.extend(child));
        return elements;
      }
    );
  },

  getInputs: function(form, typeName, name) {
    form = $(form);
    var inputs = form.getElementsByTagName('input');

    if (!typeName && !name) return $A(inputs).map(Element.extend);

    for (var i = 0, matchingInputs = [], length = inputs.length; i < length; i++) {
      var input = inputs[i];
      if ((typeName && input.type != typeName) || (name && input.name != name))
        continue;
      matchingInputs.push(Element.extend(input));
    }

    return matchingInputs;
  },

  disable: function(form) {
    form = $(form);
    Form.getElements(form).invoke('disable');
    return form;
  },

  enable: function(form) {
    form = $(form);
    Form.getElements(form).invoke('enable');
    return form;
  },

  findFirstElement: function(form) {
    var elements = $(form).getElements().findAll(function(element) {
      return 'hidden' != element.type && !element.disabled;
    });
    var firstByIndex = elements.findAll(function(element) {
      return element.hasAttribute('tabIndex') && element.tabIndex >= 0;
    }).sortBy(function(element) { return element.tabIndex }).first();

    return firstByIndex ? firstByIndex : elements.find(function(element) {
      return ['input', 'select', 'textarea'].include(element.tagName.toLowerCase());
    });
  },

  focusFirstElement: function(form) {
    form = $(form);
    form.findFirstElement().activate();
    return form;
  },

  request: function(form, options) {
    form = $(form), options = Object.clone(options || { });

    var params = options.parameters, action = form.readAttribute('action') || '';
    if (action.blank()) action = window.location.href;
    options.parameters = form.serialize(true);

    if (params) {
      if (Object.isString(params)) params = params.toQueryParams();
      Object.extend(options.parameters, params);
    }

    if (form.hasAttribute('method') && !options.method)
      options.method = form.method;

    return new Ajax.Request(action, options);
  }
};

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

Form.Element = {
  focus: function(element) {
    $(element).focus();
    return element;
  },

  select: function(element) {
    $(element).select();
    return element;
  }
};

Form.Element.Methods = {
  serialize: function(element) {
    element = $(element);
    if (!element.disabled && element.name) {
      var value = element.getValue();
      if (value != undefined) {
        var pair = { };
        pair[element.name] = value;
        return Object.toQueryString(pair);
      }
    }
    return '';
  },

  getValue: function(element) {
    element = $(element);
    var method = element.tagName.toLowerCase();
    return Form.Element.Serializers[method](element);
  },

  setValue: function(element, value) {
    element = $(element);
    var method = element.tagName.toLowerCase();
    Form.Element.Serializers[method](element, value);
    return element;
  },

  clear: function(element) {
    $(element).value = '';
    return element;
  },

  present: function(element) {
    return $(element).value != '';
  },

  activate: function(element) {
    element = $(element);
    try {
      element.focus();
      if (element.select && (element.tagName.toLowerCase() != 'input' ||
          !['button', 'reset', 'submit'].include(element.type)))
        element.select();
    } catch (e) { }
    return element;
  },

  disable: function(element) {
    element = $(element);
    element.blur();
    element.disabled = true;
    return element;
  },

  enable: function(element) {
    element = $(element);
    element.disabled = false;
    return element;
  }
};

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

var Field = Form.Element;
var $F = Form.Element.Methods.getValue;

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

Form.Element.Serializers = {
  input: function(element, value) {
    switch (element.type.toLowerCase()) {
      case 'checkbox':
      case 'radio':
        return Form.Element.Serializers.inputSelector(element, value);
      default:
        return Form.Element.Serializers.textarea(element, value);
    }
  },

  inputSelector: function(element, value) {
    if (Object.isUndefined(value)) return element.checked ? element.value : null;
    else element.checked = !!value;
  },

  textarea: function(element, value) {
    if (Object.isUndefined(value)) return element.value;
    else element.value = value;
  },

  select: function(element, index) {
    if (Object.isUndefined(index))
      return this[element.type == 'select-one' ?
        'selectOne' : 'selectMany'](element);
    else {
      var opt, value, single = !Object.isArray(index);
      for (var i = 0, length = element.length; i < length; i++) {
        opt = element.options[i];
        value = this.optionValue(opt);
        if (single) {
          if (value == index) {
            opt.selected = true;
            return;
          }
        }
        else opt.selected = index.include(value);
      }
    }
  },

  selectOne: function(element) {
    var index = element.selectedIndex;
    return index >= 0 ? this.optionValue(element.options[index]) : null;
  },

  selectMany: function(element) {
    var values, length = element.length;
    if (!length) return null;

    for (var i = 0, values = []; i < length; i++) {
      var opt = element.options[i];
      if (opt.selected) values.push(this.optionValue(opt));
    }
    return values;
  },

  optionValue: function(opt) {
    // extend element because hasAttribute may not be native
    return Element.extend(opt).hasAttribute('value') ? opt.value : opt.text;
  }
};

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

Abstract.TimedObserver = Class.create(PeriodicalExecuter, {
  initialize: function($super, element, frequency, callback) {
    $super(callback, frequency);
    this.element   = $(element);
    this.lastValue = this.getValue();
  },

  execute: function() {
    var value = this.getValue();
    if (Object.isString(this.lastValue) && Object.isString(value) ?
        this.lastValue != value : String(this.lastValue) != String(value)) {
      this.callback(this.element, value);
      this.lastValue = value;
    }
  }
});

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

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

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

Abstract.EventObserver = Class.create({
  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() {
    Form.getElements(this.element).each(this.registerCallback, this);
  },

  registerCallback: function(element) {
    if (element.type) {
      switch (element.type.toLowerCase()) {
        case 'checkbox':
        case 'radio':
          Event.observe(element, 'click', this.onElementEvent.bind(this));
          break;
        default:
          Event.observe(element, 'change', this.onElementEvent.bind(this));
          break;
      }
    }
  }
});

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

Form.EventObserver = Class.create(Abstract.EventObserver, {
  getValue: function() {
    return Form.serialize(this.element);
  }
});
if (!window.Event) var Event = { };

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,
  KEY_HOME:     36,
  KEY_END:      35,
  KEY_PAGEUP:   33,
  KEY_PAGEDOWN: 34,
  KEY_INSERT:   45,

  cache: { },

  relatedTarget: function(event) {
    var element;
    switch(event.type) {
      case 'mouseover': element = event.fromElement; break;
      case 'mouseout':  element = event.toElement;   break;
      default: return null;
    }
    return Element.extend(element);
  }
});

Event.Methods = (function() {
  var isButton;

  if (Prototype.Browser.IE) {
    var buttonMap = { 0: 1, 1: 4, 2: 2 };
    isButton = function(event, code) {
      return event.button == buttonMap[code];
    };

  } else if (Prototype.Browser.WebKit) {
    isButton = function(event, code) {
      switch (code) {
        case 0: return event.which == 1 && !event.metaKey;
        case 1: return event.which == 1 && event.metaKey;
        default: return false;
      }
    };

  } else {
    isButton = function(event, code) {
      return event.which ? (event.which === code + 1) : (event.button === code);
    };
  }

  return {
    isLeftClick:   function(event) { return isButton(event, 0) },
    isMiddleClick: function(event) { return isButton(event, 1) },
    isRightClick:  function(event) { return isButton(event, 2) },

    element: function(event) {
      var node = Event.extend(event).target;
      return Element.extend(node.nodeType == Node.TEXT_NODE ? node.parentNode : node);
    },

    findElement: function(event, expression) {
      var element = Event.element(event);
      if (!expression) return element;
      var elements = [element].concat(element.ancestors());
      return Selector.findElement(elements, expression, 0);
    },

    pointer: function(event) {
      return {
        x: event.pageX || (event.clientX +
          (document.documentElement.scrollLeft || document.body.scrollLeft)),
        y: event.pageY || (event.clientY +
          (document.documentElement.scrollTop || document.body.scrollTop))
      };
    },

    pointerX: function(event) { return Event.pointer(event).x },
    pointerY: function(event) { return Event.pointer(event).y },

    stop: function(event) {
      Event.extend(event);
      event.preventDefault();
      event.stopPropagation();
      event.stopped = true;
    }
  };
})();

Event.extend = (function() {
  var methods = Object.keys(Event.Methods).inject({ }, function(m, name) {
    m[name] = Event.Methods[name].methodize();
    return m;
  });

  if (Prototype.Browser.IE) {
    Object.extend(methods, {
      stopPropagation: function() { this.cancelBubble = true },
      preventDefault:  function() { this.returnValue = false },
      inspect: function() { return "[object Event]" }
    });

    return function(event) {
      if (!event) return false;
      if (event._extendedByPrototype) return event;

      event._extendedByPrototype = Prototype.emptyFunction;
      var pointer = Event.pointer(event);
      Object.extend(event, {
        target: event.srcElement,
        relatedTarget: Event.relatedTarget(event),
        pageX:  pointer.x,
        pageY:  pointer.y
      });
      return Object.extend(event, methods);
    };

  } else {
    Event.prototype = Event.prototype || document.createEvent("HTMLEvents").__proto__;
    Object.extend(Event.prototype, methods);
    return Prototype.K;
  }
})();

Object.extend(Event, (function() {
  var cache = Event.cache;

  function getEventID(element) {
    if (element._prototypeEventID) return element._prototypeEventID[0];
    arguments.callee.id = arguments.callee.id || 1;
    return element._prototypeEventID = [++arguments.callee.id];
  }

  function getDOMEventName(eventName) {
    if (eventName && eventName.include(':')) return "dataavailable";
    return eventName;
  }

  function getCacheForID(id) {
    return cache[id] = cache[id] || { };
  }

  function getWrappersForEventName(id, eventName) {
    var c = getCacheForID(id);
    return c[eventName] = c[eventName] || [];
  }

  function createWrapper(element, eventName, handler) {
    var id = getEventID(element);
    var c = getWrappersForEventName(id, eventName);
    if (c.pluck("handler").include(handler)) return false;

    var wrapper = function(event) {
      if (!Event || !Event.extend ||
        (event.eventName && event.eventName != eventName))
          return false;

      Event.extend(event);
      handler.call(element, event);
    };

    wrapper.handler = handler;
    c.push(wrapper);
    return wrapper;
  }

  function findWrapper(id, eventName, handler) {
    var c = getWrappersForEventName(id, eventName);
    return c.find(function(wrapper) { return wrapper.handler == handler });
  }

  function destroyWrapper(id, eventName, handler) {
    var c = getCacheForID(id);
    if (!c[eventName]) return false;
    c[eventName] = c[eventName].without(findWrapper(id, eventName, handler));
  }

  function destroyCache() {
    for (var id in cache)
      for (var eventName in cache[id])
        cache[id][eventName] = null;
  }

  if (window.attachEvent) {
    window.attachEvent("onunload", destroyCache);
  }

  return {
    observe: function(element, eventName, handler) {
      element = $(element);
      var name = getDOMEventName(eventName);

      var wrapper = createWrapper(element, eventName, handler);
      if (!wrapper) return element;

      if (element.addEventListener) {
        element.addEventListener(name, wrapper, false);
      } else {
        element.attachEvent("on" + name, wrapper);
      }

      return element;
    },

    stopObserving: function(element, eventName, handler) {
      element = $(element);
      var id = getEventID(element), name = getDOMEventName(eventName);

      if (!handler && eventName) {
        getWrappersForEventName(id, eventName).each(function(wrapper) {
          element.stopObserving(eventName, wrapper.handler);
        });
        return element;

      } else if (!eventName) {
        Object.keys(getCacheForID(id)).each(function(eventName) {
          element.stopObserving(eventName);
        });
        return element;
      }

      var wrapper = findWrapper(id, eventName, handler);
      if (!wrapper) return element;

      if (element.removeEventListener) {
        element.removeEventListener(name, wrapper, false);
      } else {
        element.detachEvent("on" + name, wrapper);
      }

      destroyWrapper(id, eventName, handler);

      return element;
    },

    fire: function(element, eventName, memo) {
      element = $(element);
      if (element == document && document.createEvent && !element.dispatchEvent)
        element = document.documentElement;

      var event;
      if (document.createEvent) {
        event = document.createEvent("HTMLEvents");
        event.initEvent("dataavailable", true, true);
      } else {
        event = document.createEventObject();
        event.eventType = "ondataavailable";
      }

      event.eventName = eventName;
      event.memo = memo || { };

      if (document.createEvent) {
        element.dispatchEvent(event);
      } else {
        element.fireEvent(event.eventType, event);
      }

      return Event.extend(event);
    }
  };
})());

Object.extend(Event, Event.Methods);

Element.addMethods({
  fire:          Event.fire,
  observe:       Event.observe,
  stopObserving: Event.stopObserving
});

Object.extend(document, {
  fire:          Element.Methods.fire.methodize(),
  observe:       Element.Methods.observe.methodize(),
  stopObserving: Element.Methods.stopObserving.methodize(),
  loaded:        false
});

(function() {
  /* Support for the DOMContentLoaded event is based on work by Dan Webb,
     Matthias Miller, Dean Edwards and John Resig. */

  var timer;

  function fireContentLoadedEvent() {
    if (document.loaded) return;
    if (timer) window.clearInterval(timer);
    document.fire("dom:loaded");
    document.loaded = true;
  }

  if (document.addEventListener) {
    if (Prototype.Browser.WebKit) {
      timer = window.setInterval(function() {
        if (/loaded|complete/.test(document.readyState))
          fireContentLoadedEvent();
      }, 0);

      Event.observe(window, "load", fireContentLoadedEvent);

    } else {
      document.addEventListener("DOMContentLoaded",
        fireContentLoadedEvent, false);
    }

  } else {
    document.write("<script id=__onDOMContentLoaded defer src=//:><\/script>");
    $("__onDOMContentLoaded").onreadystatechange = function() {
      if (this.readyState == "complete") {
        this.onreadystatechange = null;
        fireContentLoadedEvent();
      }
    };
  }
})();
/*------------------------------- DEPRECATED -------------------------------*/

Hash.toQueryString = Object.toQueryString;

var Toggle = { display: Element.toggle };

Element.Methods.childOf = Element.Methods.descendantOf;

var Insertion = {
  Before: function(element, content) {
    return Element.insert(element, {before:content});
  },

  Top: function(element, content) {
    return Element.insert(element, {top:content});
  },

  Bottom: function(element, content) {
    return Element.insert(element, {bottom:content});
  },

  After: function(element, content) {
    return Element.insert(element, {after:content});
  }
};

var $continue = new Error('"throw $continue" is deprecated, use "return" instead');

// This should be moved to script.aculo.us; notice the deprecated methods
// further below, that map to the newer Element methods.
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;
  },

  // 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 = Element.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 = Element.cumulativeScrollOffset(element);

    this.xcomp = x + offsetcache[0] - this.deltaX;
    this.ycomp = y + offsetcache[1] - this.deltaY;
    this.offset = Element.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;
  },

  // Deprecation layer -- use newer Element methods now (1.5.2).

  cumulativeOffset: Element.Methods.cumulativeOffset,

  positionedOffset: Element.Methods.positionedOffset,

  absolutize: function(element) {
    Position.prepare();
    return Element.absolutize(element);
  },

  relativize: function(element) {
    Position.prepare();
    return Element.relativize(element);
  },

  realOffset: Element.Methods.cumulativeScrollOffset,

  offsetParent: Element.Methods.getOffsetParent,

  page: Element.Methods.viewportOffset,

  clone: function(source, target, options) {
    options = options || { };
    return Element.clonePosition(target, source, options);
  }
};

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

if (!document.getElementsByClassName) document.getElementsByClassName = function(instanceMethods){
  function iter(name) {
    return name.blank() ? null : "[contains(concat(' ', @class, ' '), ' " + name + " ')]";
  }

  instanceMethods.getElementsByClassName = Prototype.BrowserFeatures.XPath ?
  function(element, className) {
    className = className.toString().strip();
    var cond = /\s/.test(className) ? $w(className).map(iter).join('') : iter(className);
    return cond ? document._getElementsByXPath('.//*' + cond, element) : [];
  } : function(element, className) {
    className = className.toString().strip();
    var elements = [], classNames = (/\s/.test(className) ? $w(className) : null);
    if (!classNames && !className) return elements;

    var nodes = $(element).getElementsByTagName('*');
    className = ' ' + className + ' ';

    for (var i = 0, child, cn; child = nodes[i]; i++) {
      if (child.className && (cn = ' ' + child.className + ' ') && (cn.include(className) ||
          (classNames && classNames.all(function(name) {
            return !name.toString().blank() && cn.include(' ' + name + ' ');
          }))))
        elements.push(Element.extend(child));
    }
    return elements;
  };

  return function(className, parentElement) {
    return $(parentElement || document.body).getElementsByClassName(className);
  };
}(Element.Methods);

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

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);

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

Element.addMethods();