/*
Copyright (c) 2008, Yahoo! Inc. All rights reserved.
Code licensed under the BSD License:
http://developer.yahoo.net/yui/license.txt
version: 2.5.1
*/
/**
 * The dom module provides helper methods for manipulating Dom elements.
 * @module dom
 *
 */

(function() {
    var Y = YAHOO.util,     // internal shorthand
        getStyle,           // for load time browser branching
        setStyle,           // ditto
        propertyCache = {}, // for faster hyphen converts
        reClassNameCache = {},          // cache regexes for className
        document = window.document;     // cache for faster lookups
    
    YAHOO.env._id_counter = YAHOO.env._id_counter || 0;     // for use with generateId (global to save state if Dom is overwritten)

    // brower detection
    var isOpera = YAHOO.env.ua.opera,
        isSafari = YAHOO.env.ua.webkit, 
        isGecko = YAHOO.env.ua.gecko,
        isIE = YAHOO.env.ua.ie; 
    
    // regex cache
    var patterns = {
        HYPHEN: /(-[a-z])/i, // to normalize get/setStyle
        ROOT_TAG: /^body|html$/i, // body for quirks mode, html for standards,
        OP_SCROLL:/^(?:inline|table-row)$/i
    };

    var toCamel = function(property) {
        if ( !patterns.HYPHEN.test(property) ) {
            return property; // no hyphens
        }
        
        if (propertyCache[property]) { // already converted
            return propertyCache[property];
        }
       
        var converted = property;
 
        while( patterns.HYPHEN.exec(converted) ) {
            converted = converted.replace(RegExp.$1,
                    RegExp.$1.substr(1).toUpperCase());
        }
        
        propertyCache[property] = converted;
        return converted;
        //return property.replace(/-([a-z])/gi, function(m0, m1) {return m1.toUpperCase()}) // cant use function as 2nd arg yet due to safari bug
    };
    
    var getClassRegEx = function(className) {
        var re = reClassNameCache[className];
        if (!re) {
            re = new RegExp('(?:^|\\s+)' + className + '(?:\\s+|$)');
            reClassNameCache[className] = re;
        }
        return re;
    };

    // branching at load instead of runtime
    if (document.defaultView && document.defaultView.getComputedStyle) { // W3C DOM method
        getStyle = function(el, property) {
            var value = null;
            
            if (property == 'float') { // fix reserved word
                property = 'cssFloat';
            }

            var computed = el.ownerDocument.defaultView.getComputedStyle(el, '');
            if (computed) { // test computed before touching for safari
                value = computed[toCamel(property)];
            }
            
            return el.style[property] || value;
        };
    } else if (document.documentElement.currentStyle && isIE) { // IE method
        getStyle = function(el, property) {                         
            switch( toCamel(property) ) {
                case 'opacity' :// IE opacity uses filter
                    var val = 100;
                    try { // will error if no DXImageTransform
                        val = el.filters['DXImageTransform.Microsoft.Alpha'].opacity;

                    } catch(e) {
                        try { // make sure its in the document
                            val = el.filters('alpha').opacity;
                        } catch(e) {
                        }
                    }
                    return val / 100;
                case 'float': // fix reserved word
                    property = 'styleFloat'; // fall through
                default: 
                    // test currentStyle before touching
                    var value = el.currentStyle ? el.currentStyle[property] : null;
                    return ( el.style[property] || value );
            }
        };
    } else { // default to inline only
        getStyle = function(el, property) { return el.style[property]; };
    }
    
    if (isIE) {
        setStyle = function(el, property, val) {
            switch (property) {
                case 'opacity':
                    if ( YAHOO.lang.isString(el.style.filter) ) { // in case not appended
                        el.style.filter = 'alpha(opacity=' + val * 100 + ')';
                        
                        if (!el.currentStyle || !el.currentStyle.hasLayout) {
                            el.style.zoom = 1; // when no layout or cant tell
                        }
                    }
                    break;
                case 'float':
                    property = 'styleFloat';
                default:
                el.style[property] = val;
            }
        };
    } else {
        setStyle = function(el, property, val) {
            if (property == 'float') {
                property = 'cssFloat';
            }
            el.style[property] = val;
        };
    }

    var testElement = function(node, method) {
        return node && node.nodeType == 1 && ( !method || method(node) );
    };

    /**
     * Provides helper methods for DOM elements.
     * @namespace YAHOO.util
     * @class Dom
     */
    YAHOO.util.Dom = {
        /**
         * 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) {
            if (el && (el.nodeType || el.item)) { // Node, or NodeList
                return el;
            }

            if (YAHOO.lang.isString(el) || !el) { // id or null
                return document.getElementById(el);
            }
            
            if (el.length !== undefined) { // array-like 
                var c = [];
                for (var i = 0, len = el.length; i < len; ++i) {
                    c[c.length] = Y.Dom.get(el[i]);
                }
                
                return c;
            }

            return el; // some other object, just pass it back
        },
    
        /**
         * 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) {
            property = toCamel(property);
            
            var f = function(element) {
                return getStyle(element, property);
            };
            
            return Y.Dom.batch(el, f, Y.Dom, true);
        },
    
        /**
         * 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) {
            property = toCamel(property);
            
            var f = function(element) {
                setStyle(element, property, val);
                
            };
            
            Y.Dom.batch(el, f, Y.Dom, true);
        },
        
        /**
         * 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) {
            var f = function(el) {
                // has to be part of document to have pageXY
                if ( (el.parentNode === null || el.offsetParent === null ||
                        this.getStyle(el, 'display') == 'none') && el != el.ownerDocument.body) {
                    return false;
                }
                
                return getXY(el);
            };
            
            return Y.Dom.batch(el, f, Y.Dom, true);
        },
        
        /**
         * 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) {
            var f = function(el) {
                var style_pos = this.getStyle(el, 'position');
                if (style_pos == 'static') { // default to relative
                    this.setStyle(el, 'position', 'relative');
                    style_pos = 'relative';
                }

                var pageXY = this.getXY(el);
                if (pageXY === false) { // has to be part of doc to have pageXY
                    return false; 
                }
                
                var delta = [ // assuming pixels; if not we will have to retry
                    parseInt( this.getStyle(el, 'left'), 10 ),
                    parseInt( this.getStyle(el, 'top'), 10 )
                ];
            
                if ( isNaN(delta[0]) ) {// in case of 'auto'
                    delta[0] = (style_pos == 'relative') ? 0 : el.offsetLeft;
                } 
                if ( isNaN(delta[1]) ) { // in case of 'auto'
                    delta[1] = (style_pos == 'relative') ? 0 : el.offsetTop;
                } 
        
                if (pos[0] !== null) { el.style.left = pos[0] - pageXY[0] + delta[0] + 'px'; }
                if (pos[1] !== null) { el.style.top = pos[1] - pageXY[1] + delta[1] + 'px'; }
              
                if (!noRetry) {
                    var newXY = this.getXY(el);

                    // if retry is true, try one more time if we miss 
                   if ( (pos[0] !== null && newXY[0] != pos[0]) || 
                        (pos[1] !== null && newXY[1] != pos[1]) ) {
                       this.setXY(el, pos, true);
                   }
                }        
        
            };
            
            Y.Dom.batch(el, f, Y.Dom, true);
        },
        
        /**
         * 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) {
                if ( (el.parentNode === null || el.offsetParent === null ||
                        this.getStyle(el, 'display') == 'none') && el != el.ownerDocument.body) {
                    return false;
                }

                var region = Y.Region.getRegion(el);
                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 a array of HTMLElements with the given class.
         * For optimized performance, include a tag and/or root node when possible.
         * @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 
         * @param {Function} apply (optional) A function to apply to each element when found 
         * @return {Array} An array of elements that have the given class name
         */
        getElementsByClassName: function(className, tag, root, apply) {
            tag = tag || '*';
            root = (root) ? Y.Dom.get(root) : null || document; 
            if (!root) {
                return [];
            }

            var nodes = [],
                elements = root.getElementsByTagName(tag),
                re = getClassRegEx(className);

            for (var i = 0, len = elements.length; i < len; ++i) {
                if ( re.test(elements[i].className) ) {
                    nodes[nodes.length] = elements[i];
                    if (apply) {
                        apply.call(elements[i], elements[i]);
                    }
                }
            }
            
            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} className the class name to search for
         * @return {Boolean | Array} A boolean value or array of boolean values
         */
        hasClass: function(el, className) {
            var re = getClassRegEx(className);

            var f = function(el) {
                return re.test(el.className);
            };
            
            return Y.Dom.batch(el, f, Y.Dom, true);
        },
    
        /**
         * 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) {
            var f = function(el) {
                if (this.hasClass(el, className)) {
                    return false; // already present
                }
                
                
                el.className = YAHOO.lang.trim([el.className, className].join(' '));
                return true;
            };
            
            return Y.Dom.batch(el, f, Y.Dom, true);
        },
    
        /**
         * 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) {
            var re = getClassRegEx(className);
            
            var f = function(el) {
                if (!className || !this.hasClass(el, className)) {
                    return false; // not present
                }                 

                
                var c = el.className;
                el.className = c.replace(re, ' ');
                if ( this.hasClass(el, className) ) { // in case of multiple adjacent
                    this.removeClass(el, className);
                }

                el.className = YAHOO.lang.trim(el.className); // remove any trailing spaces
                return true;
            };
            
            return Y.Dom.batch(el, f, Y.Dom, true);
        },
        
        /**
         * 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) {
            if (!newClassName || oldClassName === newClassName) { // avoid infinite loop
                return false;
            }
            
            var re = getClassRegEx(oldClassName);

            var f = function(el) {
            
                if ( !this.hasClass(el, oldClassName) ) {
                    this.addClass(el, newClassName); // just add it if nothing to replace
                    return true; // NOTE: return
                }
            
                el.className = el.className.replace(re, ' ' + newClassName + ' ');

                if ( this.hasClass(el, oldClassName) ) { // in case of multiple adjacent
                    this.replaceClass(el, oldClassName, newClassName);
                }

                el.className = YAHOO.lang.trim(el.className); // remove any trailing spaces
                return true;
            };
            
            return Y.Dom.batch(el, f, Y.Dom, true);
        },
        
        /**
         * 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
                    return el.id;
                } 

                var id = prefix + YAHOO.env._id_counter++;

                if (el) {
                    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);
            
            if (!haystack || !needle) {
                return false;
            }

            if (haystack.contains && needle.nodeType && !isSafari) { // safari contains is broken
                return haystack.contains(needle);
            }
            else if ( haystack.compareDocumentPosition && needle.nodeType ) {
                return !!(haystack.compareDocumentPosition(needle) & 16);
            } else if (needle.nodeType) {
                // fallback to crawling up (safari)
                return !!this.getAncestorBy(needle, function(el) {
                    return el == haystack; 
                }); 
            }
            return false;
        },
        
        /**
         * Determines whether an HTMLElement is present in the current document.
         * @method inDocument         
         * @param {String | HTMLElement} el The element to search for
         * @return {Boolean} Whether or not the element is present in the current document
         */
        inDocument: function(el) {
            return this.isAncestor(document.documentElement, el);
        },
        
        /**
         * Returns a array of HTMLElements that pass the test applied by supplied boolean method.
         * For optimized performance, include a tag and/or root node when possible.
         * @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 
         * @return {Array} Array of HTMLElements
         */
        getElementsBy: function(method, tag, root, apply) {
            tag = tag || '*';
            root = (root) ? Y.Dom.get(root) : null || document; 

            if (!root) {
                return [];
            }

            var nodes = [],
                elements = root.getElementsByTagName(tag);
            
            for (var i = 0, len = elements.length; i < len; ++i) {
                if ( method(elements[i]) ) {
                    nodes[nodes.length] = elements[i];
                    if (apply) {
                        apply(elements[i]);
                    }
                }
            }

            
            return nodes;
        },
        
        /**
         * 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} override (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, override) {
            el = (el && (el.tagName || el.item)) ? el : Y.Dom.get(el); // skip get() when possible

            if (!el || !method) {
                return false;
            } 
            var scope = (override) ? o : window;
            
            if (el.tagName || el.length === undefined) { // element or not array-like 
                return method.call(scope, el, o);
            } 

            var collection = [];
            
            for (var i = 0, len = el.length; i < len; ++i) {
                collection[collection.length] = method.call(scope, el[i], o);
            }
            
            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.compatMode != 'CSS1Compat') ? document.body.scrollHeight : document.documentElement.scrollHeight;

            var h = Math.max(scrollHeight, Y.Dom.getViewportHeight());
            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.compatMode != 'CSS1Compat') ? document.body.scrollWidth : document.documentElement.scrollWidth;
            var w = Math.max(scrollWidth, Y.Dom.getViewportWidth());
            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
            var mode = document.compatMode;
        
            if ( (mode || isIE) && !isOpera ) { // IE, Gecko
                height = (mode == 'CSS1Compat') ?
                        document.documentElement.clientHeight : // Standards
                        document.body.clientHeight; // Quirks
            }
        
            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
            var mode = document.compatMode;
            
            if (mode || isIE) { // IE, Gecko, Opera
                width = (mode == 'CSS1Compat') ?
                        document.documentElement.clientWidth : // Standards
                        document.body.clientWidth; // Quirks
            }
            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.parentNode) { // NOTE: assignment
                if ( testElement(node, method) ) {
                    return node;
                }
            } 

            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) {
                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) {
                return null;
            }
            var method = function(el) {
                 return el.tagName && el.tagName.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 ( 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) {
                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 ( 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) {
                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 = ( 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) {
                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) {
                return null;
            }
            var child = ( 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);
            var 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) {
            }

            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.documentElement.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.documentElement.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.parentNode) {
                return null;
            }       

            return referenceNode.parentNode.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.parentNode) {
                return null;
            }       

            if (referenceNode.nextSibling) {
                return referenceNode.parentNode.insertBefore(newNode, referenceNode.nextSibling); 
            } else {
                return referenceNode.parentNode.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);
        }
    };
    
    var getXY = function() {
        if (document.documentElement.getBoundingClientRect) { // IE
            return function(el) {
                var box = el.getBoundingClientRect();

                var rootNode = el.ownerDocument;
                return [box.left + Y.Dom.getDocumentScrollLeft(rootNode), box.top +
                        Y.Dom.getDocumentScrollTop(rootNode)];
            };
        } else {
            return function(el) { // manually calculate by crawling up offsetParents
                var pos = [el.offsetLeft, el.offsetTop];
                var parentNode = el.offsetParent;

                // safari: subtract body offsets if el is abs (or any offsetParent), unless body is offsetParent
                var accountForBody = (isSafari &&
                        Y.Dom.getStyle(el, 'position') == 'absolute' &&
                        el.offsetParent == el.ownerDocument.body);

                if (parentNode != el) {
                    while (parentNode) {
                        pos[0] += parentNode.offsetLeft;
                        pos[1] += parentNode.offsetTop;
                        if (!accountForBody && isSafari && 
                                Y.Dom.getStyle(parentNode,'position') == 'absolute' ) { 
                            accountForBody = true;
                        }
                        parentNode = parentNode.offsetParent;
                    }
                }

                if (accountForBody) { //safari doubles in this case
                    pos[0] -= el.ownerDocument.body.offsetLeft;
                    pos[1] -= el.ownerDocument.body.offsetTop;
                } 
                parentNode = el.parentNode;

                // account for any scrolled ancestors
                while ( parentNode.tagName && !patterns.ROOT_TAG.test(parentNode.tagName) ) 
                {
                    if (parentNode.scrollTop || parentNode.scrollLeft) {
                        // work around opera inline/table scrollLeft/Top bug (false reports offset as scroll)
                        if (!patterns.OP_SCROLL.test(Y.Dom.getStyle(parentNode, 'display'))) { 
                            if (!isOpera || Y.Dom.getStyle(parentNode, 'overflow') !== 'visible') { // opera inline-block misreports when visible
                                pos[0] -= parentNode.scrollLeft;
                                pos[1] -= parentNode.scrollTop;
                            }
                        }
                    }
                    
                    parentNode = parentNode.parentNode; 
                }

                return pos;
            };
        }
    }() // NOTE: Executing for loadtime branching
})();
/**
 * 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 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 as index, for symmetry with set/getXY
     * @property 0
     * @type Int
     */
    this[0] = l;
};

/**
 * 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    );

};

/**
 * 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    );
    var r = Math.min( this.right,  region.right  );
    var b = Math.min( this.bottom, region.bottom );
    var 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    );
    var r = Math.max( this.right,  region.right  );
    var b = Math.max( this.bottom, region.bottom );
    var 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   + 
             "}" );
};

/**
 * 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);

    var t = p[1];
    var r = p[0] + el.offsetWidth;
    var b = p[1] + el.offsetHeight;
    var 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];
   }
   
    /**
     * The X position of the point, which is also the right, left and index zero (for Dom.getXY symmetry)
     * @property x
     * @type Int
     */

    this.x = this.right = this.left = this[0] = x;
     
    /**
     * The Y position of the point, which is also the top, bottom and index one (for Dom.getXY symmetry)
     * @property y
     * @type Int
     */
    this.y = this.top = this.bottom = this[1] = y;
};

YAHOO.util.Point.prototype = new YAHOO.util.Region();

YAHOO.register("dom", YAHOO.util.Dom, {version: "2.5.1", build: "984"});
