API: element Element.js (YUI Library)

# Yahoo! UI Library

### element 2.9.0

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    (function() {
    // internal shorthand
    var Dom = YAHOO.util.Dom,
        AttributeProvider = YAHOO.util.AttributeProvider,
    	specialTypes = {
    		mouseenter: true,
    		mouseleave: true
    	};

    /**
     * Element provides an wrapper object to simplify adding
     * event listeners, using dom methods, and managing attributes.
     * @module element
     * @namespace YAHOO.util
     * @requires yahoo, dom, event
     */

    /**
     * Element provides an wrapper object to simplify adding
     * event listeners, using dom methods, and managing attributes.
     * @class Element
     * @uses YAHOO.util.AttributeProvider
     * @constructor
     * @param el {HTMLElement | String} The html element that
     * represents the Element.
     * @param {Object} map A key-value map of initial config names and values
     */
    var Element = function(el, map) {
        this.init.apply(this, arguments);
    };

    Element.DOM_EVENTS = {
        'click': true,
        'dblclick': true,
        'keydown': true,
        'keypress': true,
        'keyup': true,
        'mousedown': true,
        'mousemove': true,
        'mouseout': true,
        'mouseover': true,
        'mouseup': true,
        'mouseenter': true,
        'mouseleave': true,
        'focus': true,
        'blur': true,
        'submit': true,
        'change': true
    };

    Element.prototype = {
        /**
         * Dom events supported by the Element instance.
         * @property DOM_EVENTS
         * @type Object
         */
        DOM_EVENTS: null,

        DEFAULT_HTML_SETTER: function(value, key) {
            var el = this.get('element');

            if (el) {
                el[key] = value;
            }

    		return value;

        },

        DEFAULT_HTML_GETTER: function(key) {
            var el = this.get('element'),
                val;

            if (el) {
                val = el[key];
            }

            return val;
        },

        /**
         * Wrapper for HTMLElement method.
         * @method appendChild
         * @param {YAHOO.util.Element || HTMLElement} child The element to append.
         * @return {HTMLElement} The appended DOM element.
         */
        appendChild: function(child) {
            child = child.get ? child.get('element') : child;
            return this.get('element').appendChild(child);
        },

        /**
         * Wrapper for HTMLElement method.
         * @method getElementsByTagName
         * @param {String} tag The tagName to collect
         * @return {HTMLCollection} A collection of DOM elements.
         */
        getElementsByTagName: function(tag) {
            return this.get('element').getElementsByTagName(tag);
        },

        /**
         * Wrapper for HTMLElement method.
         * @method hasChildNodes
         * @return {Boolean} Whether or not the element has childNodes
         */
        hasChildNodes: function() {
            return this.get('element').hasChildNodes();
        },

        /**
         * Wrapper for HTMLElement method.
         * @method insertBefore
         * @param {HTMLElement} element The HTMLElement to insert
         * @param {HTMLElement} before The HTMLElement to insert
         * the element before.
         * @return {HTMLElement} The inserted DOM element.
         */
        insertBefore: function(element, before) {
            element = element.get ? element.get('element') : element;
            before = (before && before.get) ? before.get('element') : before;

            return this.get('element').insertBefore(element, before);
        },

        /**
         * Wrapper for HTMLElement method.
         * @method removeChild
         * @param {HTMLElement} child The HTMLElement to remove
         * @return {HTMLElement} The removed DOM element.
         */
        removeChild: function(child) {
            child = child.get ? child.get('element') : child;
            return this.get('element').removeChild(child);
        },

        /**
         * Wrapper for HTMLElement method.
         * @method replaceChild
         * @param {HTMLElement} newNode The HTMLElement to insert
         * @param {HTMLElement} oldNode The HTMLElement to replace
         * @return {HTMLElement} The replaced DOM element.
         */
        replaceChild: function(newNode, oldNode) {
            newNode = newNode.get ? newNode.get('element') : newNode;
            oldNode = oldNode.get ? oldNode.get('element') : oldNode;
            return this.get('element').replaceChild(newNode, oldNode);
        },

        /**
         * Registers Element specific attributes.
         * @method initAttributes
         * @param {Object} map A key-value map of initial attribute configs
         */
        initAttributes: function(map) {
        },

        /**
         * Adds a listener for the given event.  These may be DOM or
         * customEvent listeners.  Any event that is fired via fireEvent
         * can be listened for.  All handlers receive an event object.
         * @method addListener
         * @param {String} type The name of the event to listen for
         * @param {Function} fn The handler to call when the event fires
         * @param {Any} obj A variable to pass to the handler
         * @param {Object} scope The object to use for the scope of the handler
         */
        addListener: function(type, fn, obj, scope) {

            scope = scope || this;

            var Event = YAHOO.util.Event,
    			el = this.get('element') || this.get('id'),
            	self = this;

    		if (specialTypes[type] && !Event._createMouseDelegate) {
    	        YAHOO.log("Using a " + type + " event requires the event-mouseenter module", "error", "Event");
    	        return false;
    		}

            if (!this._events[type]) { // create on the fly

                if (el && this.DOM_EVENTS[type]) {
    				Event.on(el, type, function(e, matchedEl) {

    					// Supplement IE with target, currentTarget relatedTarget

    	                if (e.srcElement && !e.target) {
    	                    e.target = e.srcElement;
    	                }

    					if ((e.toElement && !e.relatedTarget) || (e.fromElement && !e.relatedTarget)) {
    						e.relatedTarget = Event.getRelatedTarget(e);
    					}

    					if (!e.currentTarget) {
    						e.currentTarget = el;
    					}

    					//	Note: matchedEl el is passed back for delegated listeners
    		            self.fireEvent(type, e, matchedEl);

    		        }, obj, scope);
                }
                this.createEvent(type, {scope: this});
            }

            return YAHOO.util.EventProvider.prototype.subscribe.apply(this, arguments); // notify via customEvent
        },

        /**
         * Alias for addListener
         * @method on
         * @param {String} type The name of the event to listen for
         * @param {Function} fn The function call when the event fires
         * @param {Any} obj A variable to pass to the handler
         * @param {Object} scope The object to use for the scope of the handler
         */
        on: function() {
            return this.addListener.apply(this, arguments);
        },

        /**
         * Alias for addListener
         * @method subscribe
         * @param {String} type The name of the event to listen for
         * @param {Function} fn The function call when the event fires
         * @param {Any} obj A variable to pass to the handler
         * @param {Object} scope The object to use for the scope of the handler
         */
        subscribe: function() {
            return this.addListener.apply(this, arguments);
        },

        /**
         * Remove an event listener
         * @method removeListener
         * @param {String} type The name of the event to listen for
         * @param {Function} fn The function call when the event fires
         */
        removeListener: function(type, fn) {
            return this.unsubscribe.apply(this, arguments);
        },

        /**
         * Wrapper for Dom method.
         * @method addClass
         * @param {String} className The className to add
         */
        addClass: function(className) {
            Dom.addClass(this.get('element'), className);
        },

        /**
         * Wrapper for Dom method.
         * @method getElementsByClassName
         * @param {String} className The className to collect
         * @param {String} tag (optional) The tag to use in
         * conjunction with class name
         * @return {Array} Array of HTMLElements
         */
        getElementsByClassName: function(className, tag) {
            return Dom.getElementsByClassName(className, tag,
                    this.get('element') );
        },

        /**
         * Wrapper for Dom method.
         * @method hasClass
         * @param {String} className The className to add
         * @return {Boolean} Whether or not the element has the class name
         */
        hasClass: function(className) {
            return Dom.hasClass(this.get('element'), className);
        },

        /**
         * Wrapper for Dom method.
         * @method removeClass
         * @param {String} className The className to remove
         */
        removeClass: function(className) {
            return Dom.removeClass(this.get('element'), className);
        },

        /**
         * Wrapper for Dom method.
         * @method replaceClass
         * @param {String} oldClassName The className to replace
         * @param {String} newClassName The className to add
         */
        replaceClass: function(oldClassName, newClassName) {
            return Dom.replaceClass(this.get('element'),
                    oldClassName, newClassName);
        },

        /**
         * Wrapper for Dom method.
         * @method setStyle
         * @param {String} property The style property to set
         * @param {String} value The value to apply to the style property
         */
        setStyle: function(property, value) {
            return Dom.setStyle(this.get('element'),  property, value); // TODO: always queuing?
        },

        /**
         * Wrapper for Dom method.
         * @method getStyle
         * @param {String} property The style property to retrieve
         * @return {String} The current value of the property
         */
        getStyle: function(property) {
            return Dom.getStyle(this.get('element'),  property);
        },

        /**
         * Apply any queued set calls.
         * @method fireQueue
         */
        fireQueue: function() {
            var queue = this._queue;
            for (var i = 0, len = queue.length; i < len; ++i) {
                this[queue[i][0]].apply(this, queue[i][1]);
            }
        },

        /**
         * Appends the HTMLElement into either the supplied parentNode.
         * @method appendTo
         * @param {HTMLElement | Element} parentNode The node to append to
         * @param {HTMLElement | Element} before An optional node to insert before
         * @return {HTMLElement} The appended DOM element.
         */
        appendTo: function(parent, before) {
            parent = (parent.get) ?  parent.get('element') : Dom.get(parent);

            this.fireEvent('beforeAppendTo', {
                type: 'beforeAppendTo',
                target: parent
            });

            before = (before && before.get) ?
                    before.get('element') : Dom.get(before);
            var element = this.get('element');

            if (!element) {
                YAHOO.log('appendTo failed: element not available',
                        'error', 'Element');
                return false;
            }

            if (!parent) {
                YAHOO.log('appendTo failed: parent not available',
                        'error', 'Element');
                return false;
            }

            if (element.parent != parent) {
                if (before) {
                    parent.insertBefore(element, before);
                } else {
                    parent.appendChild(element);
                }
            }

            YAHOO.log(element + 'appended to ' + parent);

            this.fireEvent('appendTo', {
                type: 'appendTo',
                target: parent
            });

            return element;
        },

        get: function(key) {
            var configs = this._configs || {},
                el = configs.element; // avoid loop due to 'element'

            if (el && !configs[key] && !YAHOO.lang.isUndefined(el.value[key]) ) {
                this._setHTMLAttrConfig(key);
            }

            return AttributeProvider.prototype.get.call(this, key);
        },

        setAttributes: function(map, silent) {
            // set based on configOrder
            var done = {},
                configOrder = this._configOrder;

            // set based on configOrder
            for (var i = 0, len = configOrder.length; i < len; ++i) {
                if (map[configOrder[i]] !== undefined) {
                    done[configOrder[i]] = true;
                    this.set(configOrder[i], map[configOrder[i]], silent);
                }
            }

            // unconfigured (e.g. Dom attributes)
            for (var att in map) {
                if (map.hasOwnProperty(att) && !done[att]) {
                    this.set(att, map[att], silent);
                }
            }
        },

        set: function(key, value, silent) {
            var el = this.get('element');
            if (!el) {
                this._queue[this._queue.length] = ['set', arguments];
                if (this._configs[key]) {
                    this._configs[key].value = value; // so "get" works while queueing

                }
                return;
            }

            // set it on the element if not configured and is an HTML attribute
            if ( !this._configs[key] && !YAHOO.lang.isUndefined(el[key]) ) {
                this._setHTMLAttrConfig(key);
            }

            return AttributeProvider.prototype.set.apply(this, arguments);
        },

        setAttributeConfig: function(key, map, init) {
            this._configOrder.push(key);
            AttributeProvider.prototype.setAttributeConfig.apply(this, arguments);
        },

        createEvent: function(type, config) {
            this._events[type] = true;
            return AttributeProvider.prototype.createEvent.apply(this, arguments);
        },

        init: function(el, attr) {
            this._initElement(el, attr);
        },

        destroy: function() {
            var el = this.get('element');
            YAHOO.util.Event.purgeElement(el, true); // purge DOM listeners recursively
            this.unsubscribeAll(); // unsubscribe all custom events

            if (el && el.parentNode) {
                el.parentNode.removeChild(el); // pull from the DOM
            }

            // revert initial configs
            this._queue = [];
            this._events = {};
            this._configs = {};
            this._configOrder = [];
        },

        _initElement: function(el, attr) {
            this._queue = this._queue || [];
            this._events = this._events || {};
            this._configs = this._configs || {};
            this._configOrder = [];
            attr = attr || {};
            attr.element = attr.element || el || null;

            var isReady = false;  // to determine when to init HTMLElement and content

            var DOM_EVENTS = Element.DOM_EVENTS;
            this.DOM_EVENTS = this.DOM_EVENTS || {};

            for (var event in DOM_EVENTS) {
                if (DOM_EVENTS.hasOwnProperty(event)) {
                    this.DOM_EVENTS[event] = DOM_EVENTS[event];
                }
            }

            if (typeof attr.element === 'string') { // register ID for get() access
                this._setHTMLAttrConfig('id', { value: attr.element });
            }

            if (Dom.get(attr.element)) {
                isReady = true;
                this._initHTMLElement(attr);
                this._initContent(attr);
            }

            YAHOO.util.Event.onAvailable(attr.element, function() {
                if (!isReady) { // otherwise already done
                    this._initHTMLElement(attr);
                }

                this.fireEvent('available', { type: 'available', target: Dom.get(attr.element) });
            }, this, true);

            YAHOO.util.Event.onContentReady(attr.element, function() {
                if (!isReady) { // otherwise already done
                    this._initContent(attr);
                }
                this.fireEvent('contentReady', { type: 'contentReady', target: Dom.get(attr.element) });
            }, this, true);
        },

        _initHTMLElement: function(attr) {
            /**
             * The HTMLElement the Element instance refers to.
             * @attribute element
             * @type HTMLElement
             */
            this.setAttributeConfig('element', {
                value: Dom.get(attr.element),
                readOnly: true
             });
        },

        _initContent: function(attr) {
            this.initAttributes(attr);
            this.setAttributes(attr, true);
            this.fireQueue();

        },

        /**
         * Sets the value of the property and fires beforeChange and change events.
         * @private
         * @method _setHTMLAttrConfig
         * @param {YAHOO.util.Element} element The Element instance to
         * register the config to.
         * @param {String} key The name of the config to register
         * @param {Object} map A key-value map of the config's params
         */
        _setHTMLAttrConfig: function(key, map) {
            var el = this.get('element');
            map = map || {};
            map.name = key;

            map.setter = map.setter || this.DEFAULT_HTML_SETTER;
            map.getter = map.getter || this.DEFAULT_HTML_GETTER;

            map.value = map.value || el[key];
            this._configs[key] = new YAHOO.util.Attribute(map, this);
        }
    };

    /**
     * Fires when the Element's HTMLElement can be retrieved by Id.
     * <p>See: <a href="#addListener">Element.addListener</a></p>
     * <p><strong>Event fields:</strong><br>
     * <code>&lt;String&gt; type</code> available<br>
     * <code>&lt;HTMLElement&gt;
     * target</code> the HTMLElement bound to this Element instance<br>
     * <p><strong>Usage:</strong><br>
     * <code>var handler = function(e) {var target = e.target};<br>
     * myTabs.addListener('available', handler);</code></p>
     * @event available
     */

    /**
     * Fires when the Element's HTMLElement subtree is rendered.
     * <p>See: <a href="#addListener">Element.addListener</a></p>
     * <p><strong>Event fields:</strong><br>
     * <code>&lt;String&gt; type</code> contentReady<br>
     * <code>&lt;HTMLElement&gt;
     * target</code> the HTMLElement bound to this Element instance<br>
     * <p><strong>Usage:</strong><br>
     * <code>var handler = function(e) {var target = e.target};<br>
     * myTabs.addListener('contentReady', handler);</code></p>
     * @event contentReady
     */

    /**
     * Fires before the Element is appended to another Element.
     * <p>See: <a href="#addListener">Element.addListener</a></p>
     * <p><strong>Event fields:</strong><br>
     * <code>&lt;String&gt; type</code> beforeAppendTo<br>
     * <code>&lt;HTMLElement/Element&gt;
     * target</code> the HTMLElement/Element being appended to
     * <p><strong>Usage:</strong><br>
     * <code>var handler = function(e) {var target = e.target};<br>
     * myTabs.addListener('beforeAppendTo', handler);</code></p>
     * @event beforeAppendTo
     */

    /**
     * Fires after the Element is appended to another Element.
     * <p>See: <a href="#addListener">Element.addListener</a></p>
     * <p><strong>Event fields:</strong><br>
     * <code>&lt;String&gt; type</code> appendTo<br>
     * <code>&lt;HTMLElement/Element&gt;
     * target</code> the HTMLElement/Element being appended to
     * <p><strong>Usage:</strong><br>
     * <code>var handler = function(e) {var target = e.target};<br>
     * myTabs.addListener('appendTo', handler);</code></p>
     * @event appendTo
     */

    YAHOO.augment(Element, AttributeProvider);
    YAHOO.util.Element = Element;
    })();

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