element.js

Ext JS是一个创建丰富互联网应用程序的跨浏览器的JavaScrip库。它包含：高效率

    },

    /**
     * Sets up event handlers to call the passed functions when the mouse is moved into and out of the Element.
     * @param {Function} overFn The function to call when the mouse enters the Element.
     * @param {Function} outFn The function to call when the mouse leaves the Element.
     * @param {Object} scope (optional) The scope (<tt>this</tt> reference) in which the functions are executed. Defaults to the Element's DOM element.
     * @param {Object} options (optional) Options for the listener. See {@link Ext.util.Observable#addListener the <tt>options</tt> parameter}.
     * @return {Ext.Element} this
     */
    hover : function(overFn, outFn, scope, options){
        var me = this;
        me.on('mouseenter', overFn, scope || me.dom, options);
        me.on('mouseleave', outFn, scope || me.dom, options);
        return me;
    },

	/**
     * Returns true if this element is an ancestor of the passed element
     * @param {HTMLElement/String} el The element to check
     * @return {Boolean} True if this element is an ancestor of el, else false
     */
    contains : function(el){
        return !el ? false : Ext.lib.Dom.isAncestor(this.dom, el.dom ? el.dom : el);
    },

    /**
     * Returns the value of a namespaced attribute from the element's underlying DOM node.
     * @param {String} namespace The namespace in which to look for the attribute
     * @param {String} name The attribute name
     * @return {String} The attribute value
     */
    getAttributeNS : Ext.isIE ? function(ns, name){
        var d = this.dom,
        	type = typeof d[ns + ":" + name];

        if(!Ext.isEmpty(type) && type != 'unknown'){
            return d[ns + ":" + name];
        }
        return d[name];
    } : function(ns, name){
        var d = this.dom;
        return d.getAttributeNS(ns, name) || d.getAttribute(ns + ":" + name) || d.getAttribute(name) || d[name];
    },
    
    update : function(html) {
	    this.dom.innerHTML = html;
    }
};

var ep = El.prototype;

El.addMethods = function(o){
   Ext.apply(ep, o);
};

/**
 * Appends an event handler (shorthand for {@link #addListener}).
 * @param {String} eventName The type of event to handle
 * @param {Function} fn The handler function the event invokes
 * @param {Object} scope (optional) The scope (this element) of the handler function
 * @param {Object} options (optional) An object containing standard {@link #addListener} options
 * @member Ext.Element
 * @method on
 */
ep.on = ep.addListener;

/**
 * Removes an event handler from this element (see {@link #removeListener} for additional notes).
 * @param {String} eventName the type of event to remove
 * @param {Function} fn the method the event invokes
 * @param {Object} scope (optional) The scope (The <tt>this</tt> reference) of the handler function. Defaults
 * to this Element.
 * @return {Ext.Element} this
 * @member Ext.Element
 * @method un
 */
ep.un = ep.removeListener;

/**
 * true to automatically adjust width and height settings for box-model issues (default to true)
 */
ep.autoBoxAdjust = true;

// private
var unitPattern = /\d+(px|em|%|en|ex|pt|in|cm|mm|pc)$/i,
	docEl;

/**
 * @private
 */
El.cache = {};

/**
 * Retrieves Ext.Element objects.
 * <p><b>This method does not retrieve {@link Ext.Component Component}s.</b> This method
 * retrieves Ext.Element objects which encapsulate DOM elements. To retrieve a Component by
 * its ID, use {@link Ext.ComponentMgr#get}.</p>
 * <p>Uses simple caching to consistently return the same object. Automatically fixes if an
 * object was recreated with the same id via AJAX or DOM.</p>
 * @param {Mixed} el The id of the node, a DOM Node or an existing Element.
 * @return {Element} The Element object (or null if no matching element was found)
 * @static
 * @member Ext.Element
 * @method get
 */
El.get = function(el){
    var ex,
     	elm,
     	id;
    if(!el){ return null; }
    if (typeof el == "string") { // element id
        if (!(elm = DOC.getElementById(el))) {
            return null;
        }
        if (ex = El.cache[el]) {
            ex.dom = elm;
        } else {
            ex = El.cache[el] = new El(elm);
        }
        return ex;
    } else if (el.tagName) { // dom element
        if(!(id = el.id)){
            id = Ext.id(el);
        }
        if(ex = El.cache[id]){
            ex.dom = el;
        }else{
            ex = El.cache[id] = new El(el);
        }
        return ex;
    } else if (el instanceof El) {
        if(el != docEl){
            el.dom = DOC.getElementById(el.id) || el.dom; // refresh dom element in case no longer valid,
                                                          // catch case where it hasn't been appended
            El.cache[el.id] = el; // in case it was created directly with Element(), let's cache it
        }
        return el;
    } else if(el.isComposite) {
        return el;
    } else if(Ext.isArray(el)) {
        return El.select(el);
    } else if(el == DOC) {
        // create a bogus element object representing the document object
        if(!docEl){
            var f = function(){};
            f.prototype = El.prototype;
            docEl = new f();
            docEl.dom = DOC;
        }
        return docEl;
    }
    return null;
};

// private
// Garbage collection - uncache elements/purge listeners on orphaned elements
// so we don't hold a reference and cause the browser to retain them
function garbageCollect(){
    if(!Ext.enableGarbageCollector){
        clearInterval(El.collectorThread);
    } else {
	    var eid,
	    	el,
	    	d;

	    for(eid in El.cache){
	        el = El.cache[eid];
	        d = el.dom;
	        // -------------------------------------------------------
	        // Determining what is garbage:
	        // -------------------------------------------------------
	        // !d
	        // dom node is null, definitely garbage
	        // -------------------------------------------------------
	        // !d.parentNode
	        // no parentNode == direct orphan, definitely garbage
	        // -------------------------------------------------------
	        // !d.offsetParent && !document.getElementById(eid)
	        // display none elements have no offsetParent so we will
	        // also try to look it up by it's id. However, check
	        // offsetParent first so we don't do unneeded lookups.
	        // This enables collection of elements that are not orphans
	        // directly, but somewhere up the line they have an orphan
	        // parent.
	        // -------------------------------------------------------
	        if(!d || !d.parentNode || (!d.offsetParent && !DOC.getElementById(eid))){
	            delete El.cache[eid];
	            if(d && Ext.enableListenerCollection){
	                Ext.EventManager.removeAll(d);
	            }
	        }
	    }
    }
}
El.collectorThreadId = setInterval(garbageCollect, 30000);

var flyFn = function(){};
flyFn.prototype = El.prototype;

// dom is optional
El.Flyweight = function(dom){
    this.dom = dom;
};

El.Flyweight.prototype = new flyFn();
El.Flyweight.prototype.isFlyweight = true;
El._flyweights = {};

/**
 * <p>Gets the globally shared flyweight Element, with the passed node as the active element. Do not store a reference to this element -
 * the dom node can be overwritten by other code. Shorthand of {@link Ext.Element#fly}</p>
 * <p>Use this to make one-time references to DOM elements which are not going to be accessed again either by
 * application code, or by Ext's classes. If accessing an element which will be processed regularly, then {@link Ext#get}
 * will be more appropriate to take advantage of the caching provided by the Ext.Element class.</p>
 * @param {String/HTMLElement} el The dom node or id
 * @param {String} named (optional) Allows for creation of named reusable flyweights to prevent conflicts
 * (e.g. internally Ext uses "_global")
 * @return {Element} The shared Element object (or null if no matching element was found)
 * @member Ext.Element
 * @method fly
 */
El.fly = function(el, named){
    var ret = null;
	named = named || '_global';

    if (el = Ext.getDom(el)) {
    	(El._flyweights[named] = El._flyweights[named] || new El.Flyweight()).dom = el;
    	ret = El._flyweights[named];
	}
	return ret;
};

/**
 * Retrieves Ext.Element objects.
 * <p><b>This method does not retrieve {@link Ext.Component Component}s.</b> This method
 * retrieves Ext.Element objects which encapsulate DOM elements. To retrieve a Component by
 * its ID, use {@link Ext.ComponentMgr#get}.</p>
 * <p>Uses simple caching to consistently return the same object. Automatically fixes if an
 * object was recreated with the same id via AJAX or DOM.</p>
 * Shorthand of {@link Ext.Element#get}
 * @param {Mixed} el The id of the node, a DOM Node or an existing Element.
 * @return {Element} The Element object (or null if no matching element was found)
 * @member Ext
 * @method get
 */
Ext.get = El.get;

/**
 * <p>Gets the globally shared flyweight Element, with the passed node as the active element. Do not store a reference to this element -
 * the dom node can be overwritten by other code. Shorthand of {@link Ext.Element#fly}</p>
 * <p>Use this to make one-time references to DOM elements which are not going to be accessed again either by
 * application code, or by Ext's classes. If accessing an element which will be processed regularly, then {@link Ext#get}
 * will be more appropriate to take advantage of the caching provided by the Ext.Element class.</p>
 * @param {String/HTMLElement} el The dom node or id
 * @param {String} named (optional) Allows for creation of named reusable flyweights to prevent conflicts
 * (e.g. internally Ext uses "_global")
 * @return {Element} The shared Element object (or null if no matching element was found)
 * @member Ext
 * @method fly
 */
Ext.fly = El.fly;

// speedy lookup for elements never to box adjust
var noBoxAdjust = Ext.isStrict ? {
    select:1
} : {
    input:1, select:1, textarea:1
};
if(Ext.isIE || Ext.isGecko){
    noBoxAdjust['button'] = 1;
}


Ext.EventManager.on(window, 'unload', function(){
    delete El.cache;
    delete El._flyweights;
});
})();