text: /**
   * The dom module provides helper methods for manipulating Dom elements.
   * @module dom
   *
   */
  
  (function() {
      // for use with generateId (global to save state if Dom is overwritten)
      YAHOO.env._id_counter = YAHOO.env._id_counter || 0;
  
      // internal shorthand
      var Y = YAHOO.util,
          lang = YAHOO.lang,
          UA = YAHOO.env.ua,
          trim = YAHOO.lang.trim,
          propertyCache = {}, // for faster hyphen converts
          reCache = {}, // cache className regexes
          RE_TABLE = /^t(?:able|d|h)$/i, // for _calcBorders
          RE_COLOR = /color$/i,
  
          // DOM aliases 
          document = window.document,     
          documentElement = document.documentElement,
  
          // string constants
          OWNER_DOCUMENT = 'ownerDocument',
          DEFAULT_VIEW = 'defaultView',
          DOCUMENT_ELEMENT = 'documentElement',
          COMPAT_MODE = 'compatMode',
          OFFSET_LEFT = 'offsetLeft',
          OFFSET_TOP = 'offsetTop',
          OFFSET_PARENT = 'offsetParent',
          PARENT_NODE = 'parentNode',
          NODE_TYPE = 'nodeType',
          TAG_NAME = 'tagName',
          SCROLL_LEFT = 'scrollLeft',
          SCROLL_TOP = 'scrollTop',
          GET_BOUNDING_CLIENT_RECT = 'getBoundingClientRect',
          GET_COMPUTED_STYLE = 'getComputedStyle',
          CURRENT_STYLE = 'currentStyle',
          CSS1_COMPAT = 'CSS1Compat',
          _BACK_COMPAT = 'BackCompat',
          _CLASS = 'class', // underscore due to reserved word
          CLASS_NAME = 'className',
          EMPTY = '',
          SPACE = ' ',
          C_START = '(?:^|\\s)',
          C_END = '(?= |$)',
          G = 'g',
          POSITION = 'position',
          FIXED = 'fixed',
          RELATIVE = 'relative',
          LEFT = 'left',
          TOP = 'top',
          MEDIUM = 'medium',
          BORDER_LEFT_WIDTH = 'borderLeftWidth',
          BORDER_TOP_WIDTH = 'borderTopWidth',
      
      // brower detection
          isOpera = UA.opera,
          isSafari = UA.webkit, 
          isGecko = UA.gecko, 
          isIE = UA.ie; 
      
      /**
       * Provides helper methods for DOM elements.
       * @namespace YAHOO.util
       * @class Dom
       * @requires yahoo, event
       */
      Y.Dom = {
          CUSTOM_ATTRIBUTES: (!documentElement.hasAttribute) ? { // IE < 8
              'for': 'htmlFor',
              'class': CLASS_NAME
          } : { // w3c
              'htmlFor': 'for',
              'className': _CLASS
          },
  
          DOT_ATTRIBUTES: {
              checked: true 
          },
  
          /**
           * Returns an HTMLElement reference.
           * @method get
           * @param {String | HTMLElement |Array} el Accepts a string to use as an ID for getting a DOM reference, an actual DOM reference, or an Array of IDs and/or HTMLElements.
           * @return {HTMLElement | Array} A DOM reference to an HTML element or an array of HTMLElements.
           */
          get: function(el) {
              var id, nodes, c, i, len, attr, ret = null;
  
              if (el) {
                  if (typeof el == 'string' || typeof el == 'number') { // id
                      id = el + '';
                      el = document.getElementById(el);
                      attr = (el) ? el.attributes : null;
                      if (el && attr && attr.id && attr.id.value === id) { // IE: avoid false match on "name" attribute
                          return el;
                      } else if (el && document.all) { // filter by name
                          el = null;
                          nodes = document.all[id];
                          if (nodes && nodes.length) {
                              for (i = 0, len = nodes.length; i < len; ++i) {
                                  if (nodes[i].id === id) {
                                      return nodes[i];
                                  }
                              }
                          }
                      }
                  } else if (Y.Element && el instanceof Y.Element) {
                      el = el.get('element');
                  } else if (!el.nodeType && 'length' in el) { // array-like 
                      c = [];
                      for (i = 0, len = el.length; i < len; ++i) {
                          c[c.length] = Y.Dom.get(el[i]);
                      }
                      
                      el = c;
                  }
  
                  ret = el;
              }
  
              return ret;
          },
      
          getComputedStyle: function(el, property) {
              if (window[GET_COMPUTED_STYLE]) {
                  return el[OWNER_DOCUMENT][DEFAULT_VIEW][GET_COMPUTED_STYLE](el, null)[property];
              } else if (el[CURRENT_STYLE]) {
                  return Y.Dom.IE_ComputedStyle.get(el, property);
              }
          },
  
          /**
           * Normalizes currentStyle and ComputedStyle.
           * @method getStyle
           * @param {String | HTMLElement |Array} el Accepts a string to use as an ID, an actual DOM reference, or an Array of IDs and/or HTMLElements.
           * @param {String} property The style property whose value is returned.
           * @return {String | Array} The current value of the style property for the element(s).
           */
          getStyle: function(el, property) {
              return Y.Dom.batch(el, Y.Dom._getStyle, property);
          },
  
          // branching at load instead of runtime
          _getStyle: function() {
              if (window[GET_COMPUTED_STYLE]) { // W3C DOM method
                  return function(el, property) {
                      property = (property === 'float') ? property = 'cssFloat' :
                              Y.Dom._toCamel(property);
  
                      var value = el.style[property],
                          computed;
                      
                      if (!value) {
                          computed = el[OWNER_DOCUMENT][DEFAULT_VIEW][GET_COMPUTED_STYLE](el, null);
                          if (computed) { // test computed before touching for safari
                              value = computed[property];
                          }
                      }
                      
                      return value;
                  };
              } else if (documentElement[CURRENT_STYLE]) {
                  return function(el, property) {                         
                      var value;
  
                      switch(property) {
                          case 'opacity' :// IE opacity uses filter
                              value = 100;
                              try { // will error if no DXImageTransform
                                  value = el.filters['DXImageTransform.Microsoft.Alpha'].opacity;
  
                              } catch(e) {
                                  try { // make sure its in the document
                                      value = el.filters('alpha').opacity;
                                  } catch(err) {
                                      YAHOO.log('getStyle: IE filter failed',
                                              'error', 'Dom');
                                  }
                              }
                              return value / 100;
                          case 'float': // fix reserved word
                              property = 'styleFloat'; // fall through
                          default: 
                              property = Y.Dom._toCamel(property);
                              value = el[CURRENT_STYLE] ? el[CURRENT_STYLE][property] : null;
                              return ( el.style[property] || value );
                      }
                  };
              }
          }(),
      
          /**
           * Wrapper for setting style properties of HTMLElements.  Normalizes "opacity" across modern browsers.
           * @method setStyle
           * @param {String | HTMLElement | Array} el Accepts a string to use as an ID, an actual DOM reference, or an Array of IDs and/or HTMLElements.
           * @param {String} property The style property to be set.
           * @param {String} val The value to apply to the given property.
           */
          setStyle: function(el, property, val) {
              Y.Dom.batch(el, Y.Dom._setStyle, { prop: property, val: val });
          },
  
          _setStyle: function() {
              if (!window.getComputedStyle && document.documentElement.currentStyle) {
                  return function(el, args) {
                      var property = Y.Dom._toCamel(args.prop),
                          val = args.val;
  
                      if (el) {
                          switch (property) {
                              case 'opacity':
                                  // remove filter if unsetting or full opacity
                                  if (val === '' || val === null || val === 1) {
                                      el.style.removeAttribute('filter');
                                  } else if ( lang.isString(el.style.filter) ) { // in case not appended
                                      el.style.filter = 'alpha(opacity=' + val * 100 + ')';
                                      
                                      if (!el[CURRENT_STYLE] || !el[CURRENT_STYLE].hasLayout) {
                                          el.style.zoom = 1; // when no layout or cant tell
                                      }
                                  }
                                  break;
                              case 'float':
                                  property = 'styleFloat';
                              default:
                              el.style[property] = val;
                          }
                      } else {
                          YAHOO.log('element ' + el + ' is undefined', 'error', 'Dom');
                      }
                  };
              } else {
                  return function(el, args) {
                      var property = Y.Dom._toCamel(args.prop),
                          val = args.val;
                      if (el) {
                          if (property == 'float') {
                              property = 'cssFloat';
                          }
                          el.style[property] = val;
                      } else {
                          YAHOO.log('element ' + el + ' is undefined', 'error', 'Dom');
                      }
                  };
              }
  
          }(),
          
          /**
           * Gets the current position of an element based on page coordinates. 
           * Element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
           * @method getXY
           * @param {String | HTMLElement | Array} el Accepts a string to use as an ID, an actual DOM
           * reference, or an Array of IDs and/or HTMLElements
           * @return {Array} The XY position of the element(s)
           */
          getXY: function(el) {
              return Y.Dom.batch(el, Y.Dom._getXY);
          },
  
          _canPosition: function(el) {
              return ( Y.Dom._getStyle(el, 'display') !== 'none' && Y.Dom._inDoc(el) );
          },
  
          _getXY: function(node) {
              var scrollLeft, scrollTop, box, doc,
                  clientTop, clientLeft,
                  round = Math.round, // TODO: round?
                  xy = false;
  
              if (Y.Dom._canPosition(node)) {
                  box = node[GET_BOUNDING_CLIENT_RECT]();
                  doc = node[OWNER_DOCUMENT];
                  scrollLeft = Y.Dom.getDocumentScrollLeft(doc);
                  scrollTop = Y.Dom.getDocumentScrollTop(doc);
                  xy = [box[LEFT], box[TOP]];
  
                  // remove IE default documentElement offset (border)
                  if (clientTop || clientLeft) {
                      xy[0] -= clientLeft;
                      xy[1] -= clientTop;
                  }
  
                  if ((scrollTop || scrollLeft)) {
                      xy[0] += scrollLeft;
                      xy[1] += scrollTop;
                  }
  
                  // gecko may return sub-pixel (non-int) values
                  xy[0] = round(xy[0]);
                  xy[1] = round(xy[1]);
              } else {
                  YAHOO.log('getXY failed: element not positionable (either not in a document or not displayed)', 'error', 'Dom');
              }
  
              return xy;
          },
          
          /**
           * Gets the current X position of an element based on page coordinates.  The element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
           * @method getX
           * @param {String | HTMLElement | Array} el Accepts a string to use as an ID, an actual DOM reference, or an Array of IDs and/or HTMLElements
           * @return {Number | Array} The X position of the element(s)
           */
          getX: function(el) {
              var f = function(el) {
                  return Y.Dom.getXY(el)[0];
              };
              
              return Y.Dom.batch(el, f, Y.Dom, true);
          },
          
          /**
           * Gets the current Y position of an element based on page coordinates.  Element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
           * @method getY
           * @param {String | HTMLElement | Array} el Accepts a string to use as an ID, an actual DOM reference, or an Array of IDs and/or HTMLElements
           * @return {Number | Array} The Y position of the element(s)
           */
          getY: function(el) {
              var f = function(el) {
                  return Y.Dom.getXY(el)[1];
              };
              
              return Y.Dom.batch(el, f, Y.Dom, true);
          },
          
          /**
           * Set the position of an html element in page coordinates, regardless of how the element is positioned.
           * The element(s) must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
           * @method setXY
           * @param {String | HTMLElement | Array} el Accepts a string to use as an ID, an actual DOM reference, or an Array of IDs and/or HTMLElements
           * @param {Array} pos Contains X & Y values for new position (coordinates are page-based)
           * @param {Boolean} noRetry By default we try and set the position a second time if the first fails
           */
          setXY: function(el, pos, noRetry) {
              Y.Dom.batch(el, Y.Dom._setXY, { pos: pos, noRetry: noRetry });
          },
  
          _setXY: function(node, args) {
              var pos = Y.Dom._getStyle(node, POSITION),
                  setStyle = Y.Dom.setStyle,
                  xy = args.pos,
                  noRetry = args.noRetry,
  
                  delta = [ // assuming pixels; if not we will have to retry
                      parseInt( Y.Dom.getComputedStyle(node, LEFT), 10 ),
                      parseInt( Y.Dom.getComputedStyle(node, TOP), 10 )
                  ],
  
                  currentXY,
                  newXY;
          
              currentXY = Y.Dom._getXY(node);
  
              if (!xy || currentXY === false) { // has to be part of doc to have xy
                  YAHOO.log('xy failed: node not available', 'error', 'Node');
                  return false; 
              }
              
              if (pos == 'static') { // default to relative
                  pos = RELATIVE;
                  setStyle(node, POSITION, pos);
              }
  
              if ( isNaN(delta[0]) ) {// in case of 'auto'
                  delta[0] = (pos == RELATIVE) ? 0 : node[OFFSET_LEFT];
              } 
              if ( isNaN(delta[1]) ) { // in case of 'auto'
                  delta[1] = (pos == RELATIVE) ? 0 : node[OFFSET_TOP];
              } 
  
              if (xy[0] !== null) { // from setX
                  setStyle(node, LEFT, xy[0] - currentXY[0] + delta[0] + 'px');
              }
  
              if (xy[1] !== null) { // from setY
                  setStyle(node, TOP, xy[1] - currentXY[1] + delta[1] + 'px');
              }
            
              if (!noRetry) {
                  newXY = Y.Dom._getXY(node);
  
                  // if retry is true, try one more time if we miss 
                 if ( (xy[0] !== null && newXY[0] != xy[0]) || 
                      (xy[1] !== null && newXY[1] != xy[1]) ) {
                     Y.Dom._setXY(node, { pos: xy, noRetry: true });
                 }
              }        
  
              YAHOO.log('setXY setting position to ' + xy, 'info', 'Node');
          },
          
          /**
           * Set the X position of an html element in page coordinates, regardless of how the element is positioned.
           * The element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
           * @method setX
           * @param {String | HTMLElement | Array} el Accepts a string to use as an ID, an actual DOM reference, or an Array of IDs and/or HTMLElements.
           * @param {Int} x The value to use as the X coordinate for the element(s).
           */
          setX: function(el, x) {
              Y.Dom.setXY(el, [x, null]);
          },
          
          /**
           * Set the Y position of an html element in page coordinates, regardless of how the element is positioned.
           * The element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
           * @method setY
           * @param {String | HTMLElement | Array} el Accepts a string to use as an ID, an actual DOM reference, or an Array of IDs and/or HTMLElements.
           * @param {Int} x To use as the Y coordinate for the element(s).
           */
          setY: function(el, y) {
              Y.Dom.setXY(el, [null, y]);
          },
          
          /**
           * Returns the region position of the given element.
           * The element must be part of the DOM tree to have a region (display:none or elements not appended return false).
           * @method getRegion
           * @param {String | HTMLElement | Array} el Accepts a string to use as an ID, an actual DOM reference, or an Array of IDs and/or HTMLElements.
           * @return {Region | Array} A Region or array of Region instances containing "top, left, bottom, right" member data.
           */
          getRegion: function(el) {
              var f = function(el) {
                  var region = false;
                  if ( Y.Dom._canPosition(el) ) {
                      region = Y.Region.getRegion(el);
                      YAHOO.log('getRegion returning ' + region, 'info', 'Dom');
                  } else {
                      YAHOO.log('getRegion failed: element not positionable (either not in a document or not displayed)', 'error', 'Dom');
                  }
  
                  return region;
              };
              
              return Y.Dom.batch(el, f, Y.Dom, true);
          },
          
          /**
           * Returns the width of the client (viewport).
           * @method getClientWidth
           * @deprecated Now using getViewportWidth.  This interface left intact for back compat.
           * @return {Int} The width of the viewable area of the page.
           */
          getClientWidth: function() {
              return Y.Dom.getViewportWidth();
          },
          
          /**
           * Returns the height of the client (viewport).
           * @method getClientHeight
           * @deprecated Now using getViewportHeight.  This interface left intact for back compat.
           * @return {Int} The height of the viewable area of the page.
           */
          getClientHeight: function() {
              return Y.Dom.getViewportHeight();
          },
  
          /**
           * Returns an array of HTMLElements with the given class.
           * For optimized performance, include a tag and/or root node when possible.
           * Note: This method operates against a live collection, so modifying the 
           * collection in the callback (removing/appending nodes, etc.) will have
           * side effects.  Instead you should iterate the returned nodes array,
           * as you would with the native "getElementsByTagName" method. 
           * @method getElementsByClassName
           * @param {String} className The class name to match against
           * @param {String} tag (optional) The tag name of the elements being collected
           * @param {String | HTMLElement} root (optional) The HTMLElement or an ID to use as the starting point.
           * This element is not included in the className scan.
           * @param {Function} apply (optional) A function to apply to each element when found 
           * @param {Any} o (optional) An optional arg that is passed to the supplied method
           * @param {Boolean} overrides (optional) Whether or not to override the scope of "method" with "o"
           * @return {Array} An array of elements that have the given class name
           */
          getElementsByClassName: function(className, tag, root, apply, o, overrides) {
              tag = tag || '*';
              root = (root) ? Y.Dom.get(root) : null || document; 
              if (!root) {
                  return [];
              }
  
              var nodes = [],
                  elements = root.getElementsByTagName(tag),
                  hasClass = Y.Dom.hasClass;
  
              for (var i = 0, len = elements.length; i < len; ++i) {
                  if ( hasClass(elements[i], className) ) {
                      nodes[nodes.length] = elements[i];
                  }
              }
              
              if (apply) {
                  Y.Dom.batch(nodes, apply, o, overrides);
              }
  
              return nodes;
          },
  
          /**
           * Determines whether an HTMLElement has the given className.
           * @method hasClass
           * @param {String | HTMLElement | Array} el The element or collection to test
           * @param {String | RegExp} className the class name to search for, or a regular
           * expression to match against
           * @return {Boolean | Array} A boolean value or array of boolean values
           */
          hasClass: function(el, className) {
              return Y.Dom.batch(el, Y.Dom._hasClass, className);
          },
  
          _hasClass: function(el, className) {
              var ret = false,
                  current;
              
              if (el && className) {
                  current = Y.Dom._getAttribute(el, CLASS_NAME) || EMPTY;
                  if (current) { // convert line breaks, tabs and other delims to spaces
                      current = current.replace(/\s+/g, SPACE);
                  }
  
                  if (className.exec) {
                      ret = className.test(current);
                  } else {
                      ret = className && (SPACE + current + SPACE).
                          indexOf(SPACE + className + SPACE) > -1;
                  }
              } else {
                  YAHOO.log('hasClass called with invalid arguments', 'warn', 'Dom');
              }
  
              return ret;
          },
      
          /**
           * Adds a class name to a given element or collection of elements.
           * @method addClass         
           * @param {String | HTMLElement | Array} el The element or collection to add the class to
           * @param {String} className the class name to add to the class attribute
           * @return {Boolean | Array} A pass/fail boolean or array of booleans
           */
          addClass: function(el, className) {
              return Y.Dom.batch(el, Y.Dom._addClass, className);
          },
  
          _addClass: function(el, className) {
              var ret = false,
                  current;
  
              if (el && className) {
                  current = Y.Dom._getAttribute(el, CLASS_NAME) || EMPTY;
                  if ( !Y.Dom._hasClass(el, className) ) {
                      Y.Dom.setAttribute(el, CLASS_NAME, trim(current + SPACE + className));
                      ret = true;
                  }
              } else {
                  YAHOO.log('addClass called with invalid arguments', 'warn', 'Dom');
              }
  
              return ret;
          },
      
          /**
           * Removes a class name from a given element or collection of elements.
           * @method removeClass         
           * @param {String | HTMLElement | Array} el The element or collection to remove the class from
           * @param {String} className the class name to remove from the class attribute
           * @return {Boolean | Array} A pass/fail boolean or array of booleans
           */
          removeClass: function(el, className) {
              return Y.Dom.batch(el, Y.Dom._removeClass, className);
          },
          
          _removeClass: function(el, className) {
              var ret = false,
                  current,
                  newClass,
                  attr;
  
              if (el && className) {
                  current = Y.Dom._getAttribute(el, CLASS_NAME) || EMPTY;
                  Y.Dom.setAttribute(el, CLASS_NAME, current.replace(Y.Dom._getClassRegex(className), EMPTY));
  
                  newClass = Y.Dom._getAttribute(el, CLASS_NAME);
                  if (current !== newClass) { // else nothing changed
                      Y.Dom.setAttribute(el, CLASS_NAME, trim(newClass)); // trim after comparing to current class
                      ret = true;
  
                      if (Y.Dom._getAttribute(el, CLASS_NAME) === '') { // remove class attribute if empty
                          attr = (el.hasAttribute && el.hasAttribute(_CLASS)) ? _CLASS : CLASS_NAME;
                          YAHOO.log('removeClass removing empty class attribute', 'info', 'Dom');
                          el.removeAttribute(attr);
                      }
                  }
  
              } else {
                  YAHOO.log('removeClass called with invalid arguments', 'warn', 'Dom');
              }
  
              return ret;
          },
          
          /**
           * Replace a class with another class for a given element or collection of elements.
           * If no oldClassName is present, the newClassName is simply added.
           * @method replaceClass  
           * @param {String | HTMLElement | Array} el The element or collection to remove the class from
           * @param {String} oldClassName the class name to be replaced
           * @param {String} newClassName the class name that will be replacing the old class name
           * @return {Boolean | Array} A pass/fail boolean or array of booleans
           */
          replaceClass: function(el, oldClassName, newClassName) {
              return Y.Dom.batch(el, Y.Dom._replaceClass, { from: oldClassName, to: newClassName });
          },
  
          _replaceClass: function(el, classObj) {
              var className,
                  from,
                  to,
                  ret = false,
                  current;
  
              if (el && classObj) {
                  from = classObj.from;
                  to = classObj.to;
  
                  if (!to) {
                      ret = false;
                  }  else if (!from) { // just add if no "from"
                      ret = Y.Dom._addClass(el, classObj.to);
                  } else if (from !== to) { // else nothing to replace
                      // May need to lead with DBLSPACE?
                      current = Y.Dom._getAttribute(el, CLASS_NAME) || EMPTY;
                      className = (SPACE + current.replace(Y.Dom._getClassRegex(from), SPACE + to).
                              replace(/\s+/g, SPACE)). // normalize white space
                              split(Y.Dom._getClassRegex(to));
  
                      // insert to into what would have been the first occurrence slot
                      className.splice(1, 0, SPACE + to);
                      Y.Dom.setAttribute(el, CLASS_NAME, trim(className.join(EMPTY)));
                      ret = true;
                  }
              } else {
                  YAHOO.log('replaceClass called with invalid arguments', 'warn', 'Dom');
              }
  
              return ret;
          },
          
          /**
           * Returns an ID and applies it to the element "el", if provided.
           * @method generateId  
           * @param {String | HTMLElement | Array} el (optional) An optional element array of elements to add an ID to (no ID is added if one is already present).
           * @param {String} prefix (optional) an optional prefix to use (defaults to "yui-gen").
           * @return {String | Array} The generated ID, or array of generated IDs (or original ID if already present on an element)
           */
          generateId: function(el, prefix) {
              prefix = prefix || 'yui-gen';
  
              var f = function(el) {
                  if (el && el.id) { // do not override existing ID
                      YAHOO.log('generateId returning existing id ' + el.id, 'info', 'Dom');
                      return el.id;
                  }
  
                  var id = prefix + YAHOO.env._id_counter++;
                  YAHOO.log('generateId generating ' + id, 'info', 'Dom');
  
                  if (el) {
                      if (el[OWNER_DOCUMENT] && el[OWNER_DOCUMENT].getElementById(id)) { // in case one already exists
                          // use failed id plus prefix to help ensure uniqueness
                          return Y.Dom.generateId(el, id + prefix);
                      }
                      el.id = id;
                  }
                  
                  return id;
              };
  
              // batch fails when no element, so just generate and return single ID
              return Y.Dom.batch(el, f, Y.Dom, true) || f.apply(Y.Dom, arguments);
          },
          
          /**
           * Determines whether an HTMLElement is an ancestor of another HTML element in the DOM hierarchy.
           * @method isAncestor
           * @param {String | HTMLElement} haystack The possible ancestor
           * @param {String | HTMLElement} needle The possible descendent
           * @return {Boolean} Whether or not the haystack is an ancestor of needle
           */
          isAncestor: function(haystack, needle) {
              haystack = Y.Dom.get(haystack);
              needle = Y.Dom.get(needle);
              
              var ret = false;
  
              if ( (haystack && needle) && (haystack[NODE_TYPE] && needle[NODE_TYPE]) ) {
                  if (haystack.contains && haystack !== needle) { // contains returns true when equal
                      ret = haystack.contains(needle);
                  }
                  else if (haystack.compareDocumentPosition) { // gecko
                      ret = !!(haystack.compareDocumentPosition(needle) & 16);
                  }
              } else {
                  YAHOO.log('isAncestor failed; invalid input: ' + haystack + ',' + needle, 'error', 'Dom');
              }
              YAHOO.log('isAncestor(' + haystack + ',' + needle + ' returning ' + ret, 'info', 'Dom');
              return ret;
          },
          
          /**
           * Determines whether an HTMLElement is present in the current document.
           * @method inDocument         
           * @param {String | HTMLElement} el The element to search for
           * @param {Object} doc An optional document to search, defaults to element's owner document 
           * @return {Boolean} Whether or not the element is present in the current document
           */
          inDocument: function(el, doc) {
              return Y.Dom._inDoc(Y.Dom.get(el), doc);
          },
  
          _inDoc: function(el, doc) {
              var ret = false;
              if (el && el[TAG_NAME]) {
                  doc = doc || el[OWNER_DOCUMENT]; 
                  ret = Y.Dom.isAncestor(doc[DOCUMENT_ELEMENT], el);
              } else {
                  YAHOO.log('inDocument failed: invalid input', 'error', 'Dom');
              }
              return ret;
          },
          
          /**
           * Returns an array of HTMLElements that pass the test applied by supplied boolean method.
           * For optimized performance, include a tag and/or root node when possible.
           * Note: This method operates against a live collection, so modifying the 
           * collection in the callback (removing/appending nodes, etc.) will have
           * side effects.  Instead you should iterate the returned nodes array,
           * as you would with the native "getElementsByTagName" method. 
           * @method getElementsBy
           * @param {Function} method - A boolean method for testing elements which receives the element as its only argument.
           * @param {String} tag (optional) The tag name of the elements being collected
           * @param {String | HTMLElement} root (optional) The HTMLElement or an ID to use as the starting point 
           * @param {Function} apply (optional) A function to apply to each element when found 
           * @param {Any} o (optional) An optional arg that is passed to the supplied method
           * @param {Boolean} overrides (optional) Whether or not to override the scope of "method" with "o"
           * @return {Array} Array of HTMLElements
           */
          getElementsBy: function(method, tag, root, apply, o, overrides, firstOnly) {
              tag = tag || '*';
              root = (root) ? Y.Dom.get(root) : null || document; 
  
                  var ret = (firstOnly) ? null : [],
                      elements;
              
              // in case Dom.get() returns null
              if (root) {
                  elements = root.getElementsByTagName(tag);
                  for (var i = 0, len = elements.length; i < len; ++i) {
                      if ( method(elements[i]) ) {
                          if (firstOnly) {
                              ret = elements[i]; 
                              break;
                          } else {
                              ret[ret.length] = elements[i];
                          }
                      }
                  }
  
                  if (apply) {
                      Y.Dom.batch(ret, apply, o, overrides);
                  }
              }
  
              YAHOO.log('getElementsBy returning ' + ret, 'info', 'Dom');
              
              return ret;
          },
          
          /**
           * Returns the first HTMLElement that passes the test applied by the supplied boolean method.
           * @method getElementBy
           * @param {Function} method - A boolean method for testing elements which receives the element as its only argument.
           * @param {String} tag (optional) The tag name of the elements being collected
           * @param {String | HTMLElement} root (optional) The HTMLElement or an ID to use as the starting point 
           * @return {HTMLElement}
           */
          getElementBy: function(method, tag, root) {
              return Y.Dom.getElementsBy(method, tag, root, null, null, null, true); 
          },
  
          /**
           * Runs the supplied method against each item in the Collection/Array.
           * The method is called with the element(s) as the first arg, and the optional param as the second ( method(el, o) ).
           * @method batch
           * @param {String | HTMLElement | Array} el (optional) An element or array of elements to apply the method to
           * @param {Function} method The method to apply to the element(s)
           * @param {Any} o (optional) An optional arg that is passed to the supplied method
           * @param {Boolean} overrides (optional) Whether or not to override the scope of "method" with "o"
           * @return {Any | Array} The return value(s) from the supplied method
           */
          batch: function(el, method, o, overrides) {
              var collection = [],
                  scope = (overrides) ? o : null;
                  
              el = (el && (el[TAG_NAME] || el.item)) ? el : Y.Dom.get(el); // skip get() when possible
              if (el && method) {
                  if (el[TAG_NAME] || el.length === undefined) { // element or not array-like 
                      return method.call(scope, el, o);
                  } 
  
                  for (var i = 0; i < el.length; ++i) {
                      collection[collection.length] = method.call(scope || el[i], el[i], o);
                  }
              } else {
                  YAHOO.log('batch called with invalid arguments', 'warn', 'Dom');
                  return false;
              } 
              return collection;
          },
          
          /**
           * Returns the height of the document.
           * @method getDocumentHeight
           * @return {Int} The height of the actual document (which includes the body and its margin).
           */
          getDocumentHeight: function() {
              var scrollHeight = (document[COMPAT_MODE] != CSS1_COMPAT || isSafari) ? document.body.scrollHeight : documentElement.scrollHeight,
                  h = Math.max(scrollHeight, Y.Dom.getViewportHeight());
  
              YAHOO.log('getDocumentHeight returning ' + h, 'info', 'Dom');
              return h;
          },
          
          /**
           * Returns the width of the document.
           * @method getDocumentWidth
           * @return {Int} The width of the actual document (which includes the body and its margin).
           */
          getDocumentWidth: function() {
              var scrollWidth = (document[COMPAT_MODE] != CSS1_COMPAT || isSafari) ? document.body.scrollWidth : documentElement.scrollWidth,
                  w = Math.max(scrollWidth, Y.Dom.getViewportWidth());
              YAHOO.log('getDocumentWidth returning ' + w, 'info', 'Dom');
              return w;
          },
  
          /**
           * Returns the current height of the viewport.
           * @method getViewportHeight
           * @return {Int} The height of the viewable area of the page (excludes scrollbars).
           */
          getViewportHeight: function() {
              var height = self.innerHeight, // Safari, Opera
                  mode = document[COMPAT_MODE];
          
              if ( (mode || isIE) && !isOpera ) { // IE, Gecko
                  height = (mode == CSS1_COMPAT) ?
                          documentElement.clientHeight : // Standards
                          document.body.clientHeight; // Quirks
              }
          
              YAHOO.log('getViewportHeight returning ' + height, 'info', 'Dom');
              return height;
          },
          
          /**
           * Returns the current width of the viewport.
           * @method getViewportWidth
           * @return {Int} The width of the viewable area of the page (excludes scrollbars).
           */
          
          getViewportWidth: function() {
              var width = self.innerWidth,  // Safari
                  mode = document[COMPAT_MODE];
              
              if (mode || isIE) { // IE, Gecko, Opera
                  width = (mode == CSS1_COMPAT) ?
                          documentElement.clientWidth : // Standards
                          document.body.clientWidth; // Quirks
              }
              YAHOO.log('getViewportWidth returning ' + width, 'info', 'Dom');
              return width;
          },
  
         /**
           * Returns the nearest ancestor that passes the test applied by supplied boolean method.
           * For performance reasons, IDs are not accepted and argument validation omitted.
           * @method getAncestorBy
           * @param {HTMLElement} node The HTMLElement to use as the starting point 
           * @param {Function} method - A boolean method for testing elements which receives the element as its only argument.
           * @return {Object} HTMLElement or null if not found
           */
          getAncestorBy: function(node, method) {
              while ( (node = node[PARENT_NODE]) ) { // NOTE: assignment
                  if ( Y.Dom._testElement(node, method) ) {
                      YAHOO.log('getAncestorBy returning ' + node, 'info', 'Dom');
                      return node;
                  }
              } 
  
              YAHOO.log('getAncestorBy returning null (no ancestor passed test)', 'error', 'Dom');
              return null;
          },
          
          /**
           * Returns the nearest ancestor with the given className.
           * @method getAncestorByClassName
           * @param {String | HTMLElement} node The HTMLElement or an ID to use as the starting point 
           * @param {String} className
           * @return {Object} HTMLElement
           */
          getAncestorByClassName: function(node, className) {
              node = Y.Dom.get(node);
              if (!node) {
                  YAHOO.log('getAncestorByClassName failed: invalid node argument', 'error', 'Dom');
                  return null;
              }
              var method = function(el) { return Y.Dom.hasClass(el, className); };
              return Y.Dom.getAncestorBy(node, method);
          },
  
          /**
           * Returns the nearest ancestor with the given tagName.
           * @method getAncestorByTagName
           * @param {String | HTMLElement} node The HTMLElement or an ID to use as the starting point 
           * @param {String} tagName
           * @return {Object} HTMLElement
           */
          getAncestorByTagName: function(node, tagName) {
              node = Y.Dom.get(node);
              if (!node) {
                  YAHOO.log('getAncestorByTagName failed: invalid node argument', 'error', 'Dom');
                  return null;
              }
              var method = function(el) {
                   return el[TAG_NAME] && el[TAG_NAME].toUpperCase() == tagName.toUpperCase();
              };
  
              return Y.Dom.getAncestorBy(node, method);
          },
  
          /**
           * Returns the previous sibling that is an HTMLElement. 
           * For performance reasons, IDs are not accepted and argument validation omitted.
           * Returns the nearest HTMLElement sibling if no method provided.
           * @method getPreviousSiblingBy
           * @param {HTMLElement} node The HTMLElement to use as the starting point 
           * @param {Function} method A boolean function used to test siblings
           * that receives the sibling node being tested as its only argument
           * @return {Object} HTMLElement or null if not found
           */
          getPreviousSiblingBy: function(node, method) {
              while (node) {
                  node = node.previousSibling;
                  if ( Y.Dom._testElement(node, method) ) {
                      return node;
                  }
              }
              return null;
          }, 
  
          /**
           * Returns the previous sibling that is an HTMLElement 
           * @method getPreviousSibling
           * @param {String | HTMLElement} node The HTMLElement or an ID to use as the starting point 
           * @return {Object} HTMLElement or null if not found
           */
          getPreviousSibling: function(node) {
              node = Y.Dom.get(node);
              if (!node) {
                  YAHOO.log('getPreviousSibling failed: invalid node argument', 'error', 'Dom');
                  return null;
              }
  
              return Y.Dom.getPreviousSiblingBy(node);
          }, 
  
          /**
           * Returns the next HTMLElement sibling that passes the boolean method. 
           * For performance reasons, IDs are not accepted and argument validation omitted.
           * Returns the nearest HTMLElement sibling if no method provided.
           * @method getNextSiblingBy
           * @param {HTMLElement} node The HTMLElement to use as the starting point 
           * @param {Function} method A boolean function used to test siblings
           * that receives the sibling node being tested as its only argument
           * @return {Object} HTMLElement or null if not found
           */
          getNextSiblingBy: function(node, method) {
              while (node) {
                  node = node.nextSibling;
                  if ( Y.Dom._testElement(node, method) ) {
                      return node;
                  }
              }
              return null;
          }, 
  
          /**
           * Returns the next sibling that is an HTMLElement 
           * @method getNextSibling
           * @param {String | HTMLElement} node The HTMLElement or an ID to use as the starting point 
           * @return {Object} HTMLElement or null if not found
           */
          getNextSibling: function(node) {
              node = Y.Dom.get(node);
              if (!node) {
                  YAHOO.log('getNextSibling failed: invalid node argument', 'error', 'Dom');
                  return null;
              }
  
              return Y.Dom.getNextSiblingBy(node);
          }, 
  
          /**
           * Returns the first HTMLElement child that passes the test method. 
           * @method getFirstChildBy
           * @param {HTMLElement} node The HTMLElement to use as the starting point 
           * @param {Function} method A boolean function used to test children
           * that receives the node being tested as its only argument
           * @return {Object} HTMLElement or null if not found
           */
          getFirstChildBy: function(node, method) {
              var child = ( Y.Dom._testElement(node.firstChild, method) ) ? node.firstChild : null;
              return child || Y.Dom.getNextSiblingBy(node.firstChild, method);
          }, 
  
          /**
           * Returns the first HTMLElement child. 
           * @method getFirstChild
           * @param {String | HTMLElement} node The HTMLElement or an ID to use as the starting point 
           * @return {Object} HTMLElement or null if not found
           */
          getFirstChild: function(node, method) {
              node = Y.Dom.get(node);
              if (!node) {
                  YAHOO.log('getFirstChild failed: invalid node argument', 'error', 'Dom');
                  return null;
              }
              return Y.Dom.getFirstChildBy(node);
          }, 
  
          /**
           * Returns the last HTMLElement child that passes the test method. 
           * @method getLastChildBy
           * @param {HTMLElement} node The HTMLElement to use as the starting point 
           * @param {Function} method A boolean function used to test children
           * that receives the node being tested as its only argument
           * @return {Object} HTMLElement or null if not found
           */
          getLastChildBy: function(node, method) {
              if (!node) {
                  YAHOO.log('getLastChild failed: invalid node argument', 'error', 'Dom');
                  return null;
              }
              var child = ( Y.Dom._testElement(node.lastChild, method) ) ? node.lastChild : null;
              return child || Y.Dom.getPreviousSiblingBy(node.lastChild, method);
          }, 
  
          /**
           * Returns the last HTMLElement child. 
           * @method getLastChild
           * @param {String | HTMLElement} node The HTMLElement or an ID to use as the starting point 
           * @return {Object} HTMLElement or null if not found
           */
          getLastChild: function(node) {
              node = Y.Dom.get(node);
              return Y.Dom.getLastChildBy(node);
          }, 
  
          /**
           * Returns an array of HTMLElement childNodes that pass the test method. 
           * @method getChildrenBy
           * @param {HTMLElement} node The HTMLElement to start from
           * @param {Function} method A boolean function used to test children
           * that receives the node being tested as its only argument
           * @return {Array} A static array of HTMLElements
           */
          getChildrenBy: function(node, method) {
              var child = Y.Dom.getFirstChildBy(node, method),
                  children = child ? [child] : [];
  
              Y.Dom.getNextSiblingBy(child, function(node) {
                  if ( !method || method(node) ) {
                      children[children.length] = node;
                  }
                  return false; // fail test to collect all children
              });
  
              return children;
          },
   
          /**
           * Returns an array of HTMLElement childNodes. 
           * @method getChildren
           * @param {String | HTMLElement} node The HTMLElement or an ID to use as the starting point 
           * @return {Array} A static array of HTMLElements
           */
          getChildren: function(node) {
              node = Y.Dom.get(node);
              if (!node) {
                  YAHOO.log('getChildren failed: invalid node argument', 'error', 'Dom');
              }
  
              return Y.Dom.getChildrenBy(node);
          },
  
          /**
           * Returns the left scroll value of the document 
           * @method getDocumentScrollLeft
           * @param {HTMLDocument} document (optional) The document to get the scroll value of
           * @return {Int}  The amount that the document is scrolled to the left
           */
          getDocumentScrollLeft: function(doc) {
              doc = doc || document;
              return Math.max(doc[DOCUMENT_ELEMENT].scrollLeft, doc.body.scrollLeft);
          }, 
  
          /**
           * Returns the top scroll value of the document 
           * @method getDocumentScrollTop
           * @param {HTMLDocument} document (optional) The document to get the scroll value of
           * @return {Int}  The amount that the document is scrolled to the top
           */
          getDocumentScrollTop: function(doc) {
              doc = doc || document;
              return Math.max(doc[DOCUMENT_ELEMENT].scrollTop, doc.body.scrollTop);
          },
  
          /**
           * Inserts the new node as the previous sibling of the reference node 
           * @method insertBefore
           * @param {String | HTMLElement} newNode The node to be inserted
           * @param {String | HTMLElement} referenceNode The node to insert the new node before 
           * @return {HTMLElement} The node that was inserted (or null if insert fails) 
           */
          insertBefore: function(newNode, referenceNode) {
              newNode = Y.Dom.get(newNode); 
              referenceNode = Y.Dom.get(referenceNode); 
              
              if (!newNode || !referenceNode || !referenceNode[PARENT_NODE]) {
                  YAHOO.log('insertAfter failed: missing or invalid arg(s)', 'error', 'Dom');
                  return null;
              }       
  
              return referenceNode[PARENT_NODE].insertBefore(newNode, referenceNode); 
          },
  
          /**
           * Inserts the new node as the next sibling of the reference node 
           * @method insertAfter
           * @param {String | HTMLElement} newNode The node to be inserted
           * @param {String | HTMLElement} referenceNode The node to insert the new node after 
           * @return {HTMLElement} The node that was inserted (or null if insert fails) 
           */
          insertAfter: function(newNode, referenceNode) {
              newNode = Y.Dom.get(newNode); 
              referenceNode = Y.Dom.get(referenceNode); 
              
              if (!newNode || !referenceNode || !referenceNode[PARENT_NODE]) {
                  YAHOO.log('insertAfter failed: missing or invalid arg(s)', 'error', 'Dom');
                  return null;
              }       
  
              if (referenceNode.nextSibling) {
                  return referenceNode[PARENT_NODE].insertBefore(newNode, referenceNode.nextSibling); 
              } else {
                  return referenceNode[PARENT_NODE].appendChild(newNode);
              }
          },
  
          /**
           * Creates a Region based on the viewport relative to the document. 
           * @method getClientRegion
           * @return {Region} A Region object representing the viewport which accounts for document scroll
           */
          getClientRegion: function() {
              var t = Y.Dom.getDocumentScrollTop(),
                  l = Y.Dom.getDocumentScrollLeft(),
                  r = Y.Dom.getViewportWidth() + l,
                  b = Y.Dom.getViewportHeight() + t;
  
              return new Y.Region(t, r, b, l);
          },
  
          /**
           * Provides a normalized attribute interface. 
           * @method setAttribute
           * @param {String | HTMLElement} el The target element for the attribute.
           * @param {String} attr The attribute to set.
           * @param {String} val The value of the attribute.
           */
          setAttribute: function(el, attr, val) {
              Y.Dom.batch(el, Y.Dom._setAttribute, { attr: attr, val: val });
          },
  
          _setAttribute: function(el, args) {
              var attr = Y.Dom._toCamel(args.attr),
                  val = args.val;
  
              if (el && el.setAttribute) {
                  // set as DOM property, except for BUTTON, which errors on property setter
                  if (Y.Dom.DOT_ATTRIBUTES[attr] && el.tagName && el.tagName != 'BUTTON') {
                      el[attr] = val;
                  } else {
                      attr = Y.Dom.CUSTOM_ATTRIBUTES[attr] || attr;
                      el.setAttribute(attr, val);
                  }
              } else {
                  YAHOO.log('setAttribute method not available for ' + el, 'error', 'Dom');
              }
          },
  
          /**
           * Provides a normalized attribute interface. 
           * @method getAttribute
           * @param {String | HTMLElement} el The target element for the attribute.
           * @param {String} attr The attribute to get.
           * @return {String} The current value of the attribute. 
           */
          getAttribute: function(el, attr) {
              return Y.Dom.batch(el, Y.Dom._getAttribute, attr);
          },
  
  
          _getAttribute: function(el, attr) {
              var val;
              attr = Y.Dom.CUSTOM_ATTRIBUTES[attr] || attr;
  
              if (Y.Dom.DOT_ATTRIBUTES[attr]) {
                  val = el[attr];
              } else if (el && 'getAttribute' in el) {
                  if (/^(?:href|src)$/.test(attr)) { // use IE flag to return exact value
                      val = el.getAttribute(attr, 2);
                  } else {
                      val = el.getAttribute(attr);
                  }
              } else {
                  YAHOO.log('getAttribute method not available for ' + el, 'error', 'Dom');
              }
  
              return val;
          },
  
          _toCamel: function(property) {
              var c = propertyCache;
  
              function tU(x,l) {
                  return l.toUpperCase();
              }
  
              return c[property] || (c[property] = property.indexOf('-') === -1 ? 
                                      property :
                                      property.replace( /-([a-z])/gi, tU ));
          },
  
          _getClassRegex: function(className) {
              var re;
              if (className !== undefined) { // allow empty string to pass
                  if (className.exec) { // already a RegExp
                      re = className;
                  } else {
                      re = reCache[className];
                      if (!re) {
                          // escape special chars (".", "[", etc.)
                          className = className.replace(Y.Dom._patterns.CLASS_RE_TOKENS, '\\$1');
                          className = className.replace(/\s+/g, SPACE); // convert line breaks and other delims
                          re = reCache[className] = new RegExp(C_START + className + C_END, G);
                      }
                  }
              }
              return re;
          },
  
          _patterns: {
              ROOT_TAG: /^body|html$/i, // body for quirks mode, html for standards,
              CLASS_RE_TOKENS: /([\.\(\)\^\$\*\+\?\|\[\]\{\}\\])/g
          },
  
  
          _testElement: function(node, method) {
              return node && node[NODE_TYPE] == 1 && ( !method || method(node) );
          },
  
          _calcBorders: function(node, xy2) {
              var t = parseInt(Y.Dom[GET_COMPUTED_STYLE](node, BORDER_TOP_WIDTH), 10) || 0,
                  l = parseInt(Y.Dom[GET_COMPUTED_STYLE](node, BORDER_LEFT_WIDTH), 10) || 0;
              if (isGecko) {
                  if (RE_TABLE.test(node[TAG_NAME])) {
                      t = 0;
                      l = 0;
                  }
              }
              xy2[0] += l;
              xy2[1] += t;
              return xy2;
          }
      };
          
      var _getComputedStyle = Y.Dom[GET_COMPUTED_STYLE];
      // fix opera computedStyle default color unit (convert to rgb)
      if (UA.opera) {
          Y.Dom[GET_COMPUTED_STYLE] = function(node, att) {
              var val = _getComputedStyle(node, att);
              if (RE_COLOR.test(att)) {
                  val = Y.Dom.Color.toRGB(val);
              }
  
              return val;
          };
  
      }
  
      // safari converts transparent to rgba(), others use "transparent"
      if (UA.webkit) {
          Y.Dom[GET_COMPUTED_STYLE] = function(node, att) {
              var val = _getComputedStyle(node, att);
  
              if (val === 'rgba(0, 0, 0, 0)') {
                  val = 'transparent'; 
              }
  
              return val;
          };
  
      }
  
      if (UA.ie && UA.ie >= 8) {
          Y.Dom.DOT_ATTRIBUTES.type = true; // IE 8 errors on input.setAttribute('type')
      }
  })();
  /**
   * A region is a representation of an object on a grid.  It is defined
   * by the top, right, bottom, left extents, so is rectangular by default.  If 
   * other shapes are required, this class could be extended to support it.
   * @namespace YAHOO.util
   * @class Region
   * @param {Int} t the top extent
   * @param {Int} r the right extent
   * @param {Int} b the bottom extent
   * @param {Int} l the left extent
   * @constructor
   */
  YAHOO.util.Region = function(t, r, b, l) {
  
      /**
       * The region's top extent
       * @property top
       * @type Int
       */
      this.top = t;
      
      /**
       * The region's top extent
       * @property y
       * @type Int
       */
      this.y = t;
      
      /**
       * The region's top extent as index, for symmetry with set/getXY
       * @property 1
       * @type Int
       */
      this[1] = t;
  
      /**
       * The region's right extent
       * @property right
       * @type int
       */
      this.right = r;
  
      /**
       * The region's bottom extent
       * @property bottom
       * @type Int
       */
      this.bottom = b;
  
      /**
       * The region's left extent
       * @property left
       * @type Int
       */
      this.left = l;
      
      /**
       * The region's left extent
       * @property x
       * @type Int
       */
      this.x = l;
      
      /**
       * The region's left extent as index, for symmetry with set/getXY
       * @property 0
       * @type Int
       */
      this[0] = l;
  
      /**
       * The region's total width 
       * @property width 
       * @type Int
       */
      this.width = this.right - this.left;
  
      /**
       * The region's total height 
       * @property height 
       * @type Int
       */
      this.height = this.bottom - this.top;
  };
  
  /**
   * Returns true if this region contains the region passed in
   * @method contains
   * @param  {Region}  region The region to evaluate
   * @return {Boolean}        True if the region is contained with this region, 
   *                          else false
   */
  YAHOO.util.Region.prototype.contains = function(region) {
      return ( region.left   >= this.left   && 
               region.right  <= this.right  && 
               region.top    >= this.top    && 
               region.bottom <= this.bottom    );
  
      // this.logger.debug("does " + this + " contain " + region + " ... " + ret);
  };
  
  /**
   * Returns the area of the region
   * @method getArea
   * @return {Int} the region's area
   */
  YAHOO.util.Region.prototype.getArea = function() {
      return ( (this.bottom - this.top) * (this.right - this.left) );
  };
  
  /**
   * Returns the region where the passed in region overlaps with this one
   * @method intersect
   * @param  {Region} region The region that intersects
   * @return {Region}        The overlap region, or null if there is no overlap
   */
  YAHOO.util.Region.prototype.intersect = function(region) {
      var t = Math.max( this.top,    region.top    ),
          r = Math.min( this.right,  region.right  ),
          b = Math.min( this.bottom, region.bottom ),
          l = Math.max( this.left,   region.left   );
      
      if (b >= t && r >= l) {
          return new YAHOO.util.Region(t, r, b, l);
      } else {
          return null;
      }
  };
  
  /**
   * Returns the region representing the smallest region that can contain both
   * the passed in region and this region.
   * @method union
   * @param  {Region} region The region that to create the union with
   * @return {Region}        The union region
   */
  YAHOO.util.Region.prototype.union = function(region) {
      var t = Math.min( this.top,    region.top    ),
          r = Math.max( this.right,  region.right  ),
          b = Math.max( this.bottom, region.bottom ),
          l = Math.min( this.left,   region.left   );
  
      return new YAHOO.util.Region(t, r, b, l);
  };
  
  /**
   * toString
   * @method toString
   * @return string the region properties
   */
  YAHOO.util.Region.prototype.toString = function() {
      return ( "Region {"    +
               "top: "       + this.top    + 
               ", right: "   + this.right  + 
               ", bottom: "  + this.bottom + 
               ", left: "    + this.left   + 
               ", height: "  + this.height + 
               ", width: "    + this.width   + 
               "}" );
  };
  
  /**
   * Returns a region that is occupied by the DOM element
   * @method getRegion
   * @param  {HTMLElement} el The element
   * @return {Region}         The region that the element occupies
   * @static
   */
  YAHOO.util.Region.getRegion = function(el) {
      var p = YAHOO.util.Dom.getXY(el),
          t = p[1],
          r = p[0] + el.offsetWidth,
          b = p[1] + el.offsetHeight,
          l = p[0];
  
      return new YAHOO.util.Region(t, r, b, l);
  };
  
  /////////////////////////////////////////////////////////////////////////////
  
  
  /**
   * A point is a region that is special in that it represents a single point on 
   * the grid.
   * @namespace YAHOO.util
   * @class Point
   * @param {Int} x The X position of the point
   * @param {Int} y The Y position of the point
   * @constructor
   * @extends YAHOO.util.Region
   */
  YAHOO.util.Point = function(x, y) {
     if (YAHOO.lang.isArray(x)) { // accept input from Dom.getXY, Event.getXY, etc.
        y = x[1]; // dont blow away x yet
        x = x[0];
     }
   
      YAHOO.util.Point.superclass.constructor.call(this, y, x, y, x);
  };
  
  YAHOO.extend(YAHOO.util.Point, YAHOO.util.Region);
  
  (function() {
  /**
   * Internal methods used to add style management functionality to DOM.
   * @module dom
   * @class IEStyle
   * @namespace YAHOO.util.Dom
   */
  
  var Y = YAHOO.util, 
      CLIENT_TOP = 'clientTop',
      CLIENT_LEFT = 'clientLeft',
      PARENT_NODE = 'parentNode',
      RIGHT = 'right',
      HAS_LAYOUT = 'hasLayout',
      PX = 'px',
      OPACITY = 'opacity',
      AUTO = 'auto',
      BORDER_LEFT_WIDTH = 'borderLeftWidth',
      BORDER_TOP_WIDTH = 'borderTopWidth',
      BORDER_RIGHT_WIDTH = 'borderRightWidth',
      BORDER_BOTTOM_WIDTH = 'borderBottomWidth',
      VISIBLE = 'visible',
      TRANSPARENT = 'transparent',
      HEIGHT = 'height',
      WIDTH = 'width',
      STYLE = 'style',
      CURRENT_STYLE = 'currentStyle',
  
  // IE getComputedStyle
  // TODO: unit-less lineHeight (e.g. 1.22)
      re_size = /^width|height$/,
      re_unit = /^(\d[.\d]*)+(em|ex|px|gd|rem|vw|vh|vm|ch|mm|cm|in|pt|pc|deg|rad|ms|s|hz|khz|%){1}?/i,
  
      ComputedStyle = {
          /**
          * @method get
          * @description Method used by DOM to get style information for IE
          * @param {HTMLElement} el The element to check
          * @param {String} property The property to check
          * @returns {String} The computed style
          */
          get: function(el, property) {
              var value = '',
                  current = el[CURRENT_STYLE][property];
  
              if (property === OPACITY) {
                  value = Y.Dom.getStyle(el, OPACITY);        
              } else if (!current || (current.indexOf && current.indexOf(PX) > -1)) { // no need to convert
                  value = current;
              } else if (Y.Dom.IE_COMPUTED[property]) { // use compute function
                  value = Y.Dom.IE_COMPUTED[property](el, property);
              } else if (re_unit.test(current)) { // convert to pixel
                  value = Y.Dom.IE.ComputedStyle.getPixel(el, property);
              } else {
                  value = current;
              }
  
              return value;
          },
          /**
          * @method getOffset
          * @description Determine the offset of an element
          * @param {HTMLElement} el The element to check
          * @param {String} prop The property to check.
          * @return {String} The offset
          */
          getOffset: function(el, prop) {
              var current = el[CURRENT_STYLE][prop],                        // value of "width", "top", etc.
                  capped = prop.charAt(0).toUpperCase() + prop.substr(1), // "Width", "Top", etc.
                  offset = 'offset' + capped,                             // "offsetWidth", "offsetTop", etc.
                  pixel = 'pixel' + capped,                               // "pixelWidth", "pixelTop", etc.
                  value = '',
                  actual;
  
              if (current == AUTO) {
                  actual = el[offset]; // offsetHeight/Top etc.
                  if (actual === undefined) { // likely "right" or "bottom"
                      value = 0;
                  }
  
                  value = actual;
                  if (re_size.test(prop)) { // account for box model diff 
                      el[STYLE][prop] = actual; 
                      if (el[offset] > actual) {
                          // the difference is padding + border (works in Standards & Quirks modes)
                          value = actual - (el[offset] - actual);
                      }
                      el[STYLE][prop] = AUTO; // revert to auto
                  }
              } else { // convert units to px
                  if (!el[STYLE][pixel] && !el[STYLE][prop]) { // need to map style.width to currentStyle (no currentStyle.pixelWidth)
                      el[STYLE][prop] = current;              // no style.pixelWidth if no style.width
                  }
                  value = el[STYLE][pixel];
              }
              return value + PX;
          },
          /**
          * @method getBorderWidth
          * @description Try to determine the width of an elements border
          * @param {HTMLElement} el The element to check
          * @param {String} property The property to check
          * @return {String} The elements border width
          */
          getBorderWidth: function(el, property) {
              // clientHeight/Width = paddingBox (e.g. offsetWidth - borderWidth)
              // clientTop/Left = borderWidth
              var value = null;
              if (!el[CURRENT_STYLE][HAS_LAYOUT]) { // TODO: unset layout?
                  el[STYLE].zoom = 1; // need layout to measure client
              }
  
              switch(property) {
                  case BORDER_TOP_WIDTH:
                      value = el[CLIENT_TOP];
                      break;
                  case BORDER_BOTTOM_WIDTH:
                      value = el.offsetHeight - el.clientHeight - el[CLIENT_TOP];
                      break;
                  case BORDER_LEFT_WIDTH:
                      value = el[CLIENT_LEFT];
                      break;
                  case BORDER_RIGHT_WIDTH:
                      value = el.offsetWidth - el.clientWidth - el[CLIENT_LEFT];
                      break;
              }
              return value + PX;
          },
          /**
          * @method getPixel
          * @description Get the pixel value from a style property
          * @param {HTMLElement} node The element to check
          * @param {String} att The attribute to check
          * @return {String} The pixel value
          */
          getPixel: function(node, att) {
              // use pixelRight to convert to px
              var val = null,
                  styleRight = node[CURRENT_STYLE][RIGHT],
                  current = node[CURRENT_STYLE][att];
  
              node[STYLE][RIGHT] = current;
              val = node[STYLE].pixelRight;
              node[STYLE][RIGHT] = styleRight; // revert
  
              return val + PX;
          },
  
          /**
          * @method getMargin
          * @description Get the margin value from a style property
          * @param {HTMLElement} node The element to check
          * @param {String} att The attribute to check
          * @return {String} The margin value
          */
          getMargin: function(node, att) {
              var val;
              if (node[CURRENT_STYLE][att] == AUTO) {
                  val = 0 + PX;
              } else {
                  val = Y.Dom.IE.ComputedStyle.getPixel(node, att);
              }
              return val;
          },
  
          /**
          * @method getVisibility
          * @description Get the visibility of an element
          * @param {HTMLElement} node The element to check
          * @param {String} att The attribute to check
          * @return {String} The value
          */
          getVisibility: function(node, att) {
              var current;
              while ( (current = node[CURRENT_STYLE]) && current[att] == 'inherit') { // NOTE: assignment in test
                  node = node[PARENT_NODE];
              }
              return (current) ? current[att] : VISIBLE;
          },
  
          /**
          * @method getColor
          * @description Get the color of an element
          * @param {HTMLElement} node The element to check
          * @param {String} att The attribute to check
          * @return {String} The value
          */
          getColor: function(node, att) {
              return Y.Dom.Color.toRGB(node[CURRENT_STYLE][att]) || TRANSPARENT;
          },
  
          /**
          * @method getBorderColor
          * @description Get the bordercolor of an element
          * @param {HTMLElement} node The element to check
          * @param {String} att The attribute to check
          * @return {String} The value
          */
          getBorderColor: function(node, att) {
              var current = node[CURRENT_STYLE],
                  val = current[att] || current.color;
              return Y.Dom.Color.toRGB(Y.Dom.Color.toHex(val));
          }
  
      },
  
  //fontSize: getPixelFont,
      IEComputed = {};
  
  IEComputed.top = IEComputed.right = IEComputed.bottom = IEComputed.left = 
          IEComputed[WIDTH] = IEComputed[HEIGHT] = ComputedStyle.getOffset;
  
  IEComputed.color = ComputedStyle.getColor;
  
  IEComputed[BORDER_TOP_WIDTH] = IEComputed[BORDER_RIGHT_WIDTH] =
          IEComputed[BORDER_BOTTOM_WIDTH] = IEComputed[BORDER_LEFT_WIDTH] =
          ComputedStyle.getBorderWidth;
  
  IEComputed.marginTop = IEComputed.marginRight = IEComputed.marginBottom =
          IEComputed.marginLeft = ComputedStyle.getMargin;
  
  IEComputed.visibility = ComputedStyle.getVisibility;
  IEComputed.borderColor = IEComputed.borderTopColor =
          IEComputed.borderRightColor = IEComputed.borderBottomColor =
          IEComputed.borderLeftColor = ComputedStyle.getBorderColor;
  
  Y.Dom.IE_COMPUTED = IEComputed;
  Y.Dom.IE_ComputedStyle = ComputedStyle;
  })();
  (function() {
  /**
   * Add style management functionality to DOM.
   * @module dom
   * @class Color
   * @namespace YAHOO.util.Dom
   */
  
  var TO_STRING = 'toString',
      PARSE_INT = parseInt,
      RE = RegExp,
      Y = YAHOO.util;
  
  Y.Dom.Color = {
      /**
      * @property KEYWORDS
      * @type Object
      * @description Color keywords used when converting to Hex
      */
      KEYWORDS: {
          black: '000',
          silver: 'c0c0c0',
          gray: '808080',
          white: 'fff',
          maroon: '800000',
          red: 'f00',
          purple: '800080',
          fuchsia: 'f0f',
          green: '008000',
          lime: '0f0',
          olive: '808000',
          yellow: 'ff0',
          navy: '000080',
          blue: '00f',
          teal: '008080',
          aqua: '0ff'
      },
      /**
      * @property re_RGB
      * @private
      * @type Regex
      * @description Regex to parse rgb(0,0,0) formatted strings
      */
      re_RGB: /^rgb\(([0-9]+)\s*,\s*([0-9]+)\s*,\s*([0-9]+)\)$/i,
      /**
      * @property re_hex
      * @private
      * @type Regex
      * @description Regex to parse #123456 formatted strings
      */
      re_hex: /^#?([0-9A-F]{2})([0-9A-F]{2})([0-9A-F]{2})$/i,
      /**
      * @property re_hex3
      * @private
      * @type Regex
      * @description Regex to parse #123 formatted strings
      */
      re_hex3: /([0-9A-F])/gi,
      /**
      * @method toRGB
      * @description Converts a hex or color string to an rgb string: rgb(0,0,0)
      * @param {String} val The string to convert to RGB notation.
      * @returns {String} The converted string
      */
      toRGB: function(val) {
          if (!Y.Dom.Color.re_RGB.test(val)) {
              val = Y.Dom.Color.toHex(val);
          }
  
          if(Y.Dom.Color.re_hex.exec(val)) {
              val = 'rgb(' + [
                  PARSE_INT(RE.$1, 16),
                  PARSE_INT(RE.$2, 16),
                  PARSE_INT(RE.$3, 16)
              ].join(', ') + ')';
          }
          return val;
      },
      /**
      * @method toHex
      * @description Converts an rgb or color string to a hex string: #123456
      * @param {String} val The string to convert to hex notation.
      * @returns {String} The converted string
      */
      toHex: function(val) {
          val = Y.Dom.Color.KEYWORDS[val] || val;
          if (Y.Dom.Color.re_RGB.exec(val)) {
              val = [
                  Number(RE.$1).toString(16),
                  Number(RE.$2).toString(16),
                  Number(RE.$3).toString(16)
              ];
  
              for (var i = 0; i < val.length; i++) {
                  if (val[i].length < 2) {
                      val[i] = '0' + val[i];
                  }
              }
  
              val = val.join('');
          }
  
          if (val.length < 6) {
              val = val.replace(Y.Dom.Color.re_hex3, '$1$1');
          }
  
          if (val !== 'transparent' && val.indexOf('#') < 0) {
              val = '#' + val;
          }
  
          return val.toUpperCase();
      }
  };
  }());
  YAHOO.register("dom", YAHOO.util.Dom, {version: "@VERSION@", build: "@BUILD@"});
  