# Yahoo! UI Library

### dom 2.4.1

Yahoo! UI Library > dom > Dom.js (source view)

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    /**
     * 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
            id_counter = 0,     // for use with generateId
            propertyCache = {}, // for faster hyphen converts
            reClassNameCache = {}; // cache regexes for className

        // 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
        };

        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 = document.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) {
                                YAHOO.log('getStyle: IE filter failed',
                                        'error', 'Dom');
                            }
                        }
                        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.tagName || el.item)) { // HTMLElement, or HTMLCollection
                    return el;
                }

                if (YAHOO.lang.isString(el) || !el) { // HTMLElement 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);
                    YAHOO.log('setStyle setting ' + property + ' to ' + val, 'info', 'Dom');

                };

                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 != document.body) {
                        YAHOO.log('getXY failed: element not available', 'error', 'Dom');
                        return false;
                    }

                    var parentNode = null;
                    var pos = [];
                    var box;
                    var doc = el.ownerDocument;

                    if (el.getBoundingClientRect) { // IE
                        box = el.getBoundingClientRect();
                        return [box.left + Y.Dom.getDocumentScrollLeft(el.ownerDocument), box.top + Y.Dom.getDocumentScrollTop(el.ownerDocument)];
                    }
                    else { // safari, opera, & gecko
                        pos = [el.offsetLeft, el.offsetTop];
                        parentNode = el.offsetParent;

                        // safari: if el is abs or any parent is abs, subtract body offsets
                        var hasAbs = this.getStyle(el, 'position') == 'absolute';

                        if (parentNode != el) {
                            while (parentNode) {
                                pos[0] += parentNode.offsetLeft;
                                pos[1] += parentNode.offsetTop;
                                if (isSafari && !hasAbs &&
                                        this.getStyle(parentNode,'position') == 'absolute' ) {
                                    hasAbs = true; // we need to offset if any parent is absolutely positioned
                                }
                                parentNode = parentNode.offsetParent;
                            }
                        }

                        if (isSafari && hasAbs) { //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) )
                    {
                       // work around opera inline/table scrollLeft/Top bug
                       if (Y.Dom.getStyle(parentNode, 'display').search(/^inline|table-row.*$/i)) {
                            pos[0] -= parentNode.scrollLeft;
                            pos[1] -= parentNode.scrollTop;
                        }

                        parentNode = parentNode.parentNode;
                    }

                    YAHOO.log('getXY returning ' + pos, 'info', 'Dom');

                    return pos;
                };

                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
                        YAHOO.log('setXY failed: element not available', 'error', 'Dom');
                        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);
                       }
                    }

                    YAHOO.log('setXY setting position to ' + pos, 'info', 'Dom');
                };

                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 != document.body) {
                        YAHOO.log('getRegion failed: element not available', 'error', 'Dom');
                        return false;
                    }

                    var region = Y.Region.getRegion(el);
                    YAHOO.log('getRegion returning ' + region, 'info', '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 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) {
                    YAHOO.log('hasClass returning ' + re.test(el.className), 'info', 'Dom');
                    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
                    }

                    YAHOO.log('addClass adding ' + className, 'info', 'Dom');

                    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 (!this.hasClass(el, className)) {
                        return false; // not present
                    }

                    YAHOO.log('removeClass removing ' + className, 'info', 'Dom');

                    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) {
                    YAHOO.log('replaceClass replacing ' + oldClassName + ' with ' + newClassName, 'info', 'Dom');

                    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
                        YAHOO.log('generateId returning existing id ' + el.id, 'info', 'Dom');
                        return el.id;
                    }

                    var id = prefix + id_counter++;
                    YAHOO.log('generateId generating ' + id, 'info', 'Dom');

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

                var f = function(node) {
                    if (haystack.contains && node.nodeType && !isSafari) { // safari contains is broken
                        YAHOO.log('isAncestor returning ' + haystack.contains(node), 'info', 'Dom');
                        return haystack.contains(node);
                    }
                    else if ( haystack.compareDocumentPosition && node.nodeType ) {
                        YAHOO.log('isAncestor returning ' + !!(haystack.compareDocumentPosition(node) & 16), 'info', 'Dom');
                        return !!(haystack.compareDocumentPosition(node) & 16);
                    } else if (node.nodeType) {
                        // fallback to crawling up (safari)
                        return !!this.getAncestorBy(node, function(el) {
                            return el == haystack;
                        });
                    }
                    YAHOO.log('isAncestor failed; most likely needle is not an HTMLElement', 'error', 'Dom');
                    return false;
                };

                return Y.Dom.batch(needle, f, Y.Dom, true);
            },

            /**
             * 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) {
                var f = function(el) { // safari contains fails for body so crawl up
                    if (isSafari) {
                        while (el = el.parentNode) { // note assignment
                            if (el == document.documentElement) {
                                return true;
                            }
                        }
                        return false;
                    }
                    return this.isAncestor(document.documentElement, el);
                };

                return Y.Dom.batch(el, f, Y.Dom, true);
            },

            /**
             * 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]);
                        }
                    }
                }

                YAHOO.log('getElementsBy returning ' + nodes, 'info', 'Dom');

                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) {
                    YAHOO.log('batch failed: invalid arguments', 'error', 'Dom');
                    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());
                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.compatMode != 'CSS1Compat') ? document.body.scrollWidth : document.documentElement.scrollWidth;
                var 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
                var mode = document.compatMode;

                if ( (mode || isIE) && !isOpera ) { // IE, Gecko
                    height = (mode == 'CSS1Compat') ?
                            document.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
                var mode = document.compatMode;

                if (mode || isIE) { // IE, Gecko, Opera
                    width = (mode == 'CSS1Compat') ?
                            document.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.parentNode) { // NOTE: assignment
                    if ( 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.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) {
                    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 ( 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 = ( 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 = ( 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) {
                    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.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) {
                    YAHOO.log('insertAfter failed: missing or invalid arg(s)', 'error', 'Dom');
                    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) {
                    YAHOO.log('insertAfter failed: missing or invalid arg(s)', 'error', 'Dom');
                    return null;
                }

                if (referenceNode.nextSibling) {
                    return referenceNode.parentNode.insertBefore(newNode, referenceNode.nextSibling);
                } else {
                    return referenceNode.parentNode.appendChild(newNode);
                }
            }
        };
    })();

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