The source code

    /**
     * @class Ext.Element
     */
    Ext.Element.addMethods({
        /**
         * Stops the specified event(s) from bubbling and optionally prevents the default action
         * @param {String/Array} eventName an event / array of events to stop from bubbling
         * @param {Boolean} preventDefault (optional) true to prevent the default action too
         * @return {Ext.Element} this
         */
        swallowEvent : function(eventName, preventDefault){
    	    var me = this;
            function fn(e){
                e.stopPropagation();
                if(preventDefault){
                    e.preventDefault();
                }
            }
            if(Ext.isArray(eventName)){
    	        Ext.each(eventName, function(e) {
                     me.on(e, fn);
                });
                return me;
            }
            me.on(eventName, fn);
            return me;
        },

        /**
         * Create an event handler on this element such that when the event fires and is handled by this element,
         * it will be relayed to another object (i.e., fired again as if it originated from that object instead).
         * @param {String} eventName The type of event to relay
         * @param {Object} object Any object that extends {@link Ext.util.Observable} that will provide the context
         * for firing the relayed event
         */
        relayEvent : function(eventName, observable){
            this.on(eventName, function(e){
                observable.fireEvent(eventName, e);
            });
        },

    	/**
         * Removes worthless text nodes
         * @param {Boolean} forceReclean (optional) By default the element
         * keeps track if it has been cleaned already so
         * you can call this over and over. However, if you update the element and
         * need to force a reclean, you can pass true.
         */
        clean : function(forceReclean){
            var me = this,
                dom = me.dom,
            	n = dom.firstChild,
            	ni = -1;

    	    if(Ext.Element.data(dom, 'isCleaned') && forceReclean !== true){
                return me;
            }

     	    while(n){
     	        var nx = n.nextSibling;
                if(n.nodeType == 3 && !/\S/.test(n.nodeValue)){
                    dom.removeChild(n);
                }else{
                    n.nodeIndex = ++ni;
                }
     	        n = nx;
     	    }
            Ext.Element.data(dom, 'isCleaned', true);
     	    return me;
     	},

        /**
         * Direct access to the Updater {@link Ext.Updater#update} method. The method takes the same object
         * parameter as {@link Ext.Updater#update}
         * @return {Ext.Element} this
         */
        load : function(){
            var um = this.getUpdater();
            um.update.apply(um, arguments);
            return this;
        },

        /**
        * Gets this element's {@link Ext.Updater Updater}
        * @return {Ext.Updater} The Updater
        */
        getUpdater : function(){
            return this.updateManager || (this.updateManager = new Ext.Updater(this));
        },

    	/**
        * Update the innerHTML of this element, optionally searching for and processing scripts
        * @param {String} html The new HTML
        * @param {Boolean} loadScripts (optional) True to look for and process scripts (defaults to false)
        * @param {Function} callback (optional) For async script loading you can be notified when the update completes
        * @return {Ext.Element} this
         */
        update : function(html, loadScripts, callback){
            html = html || "";

            if(loadScripts !== true){
                this.dom.innerHTML = html;
                if(Ext.isFunction(callback)){
                    callback();
                }
                return this;
            }

            var id = Ext.id(),
            	dom = this.dom;

            html += '';

            Ext.lib.Event.onAvailable(id, function(){
                var DOC = document,
                    hd = DOC.getElementsByTagName("head")[0],
                	re = /(?:]*)?>)((\n|\r|.)*?)(?:<\/script>)/ig,
                	srcRe = /\ssrc=([\'\"])(.*?)\1/i,
                	typeRe = /\stype=([\'\"])(.*?)\1/i,
                	match,
                	attrs,
                	srcMatch,
                	typeMatch,
                	el,
                	s;

                while((match = re.exec(html))){
                    attrs = match[1];
                    srcMatch = attrs ? attrs.match(srcRe) : false;
                    if(srcMatch && srcMatch[2]){
                       s = DOC.createElement("script");
                       s.src = srcMatch[2];
                       typeMatch = attrs.match(typeRe);
                       if(typeMatch && typeMatch[2]){
                           s.type = typeMatch[2];
                       }
                       hd.appendChild(s);
                    }else if(match[2] && match[2].length > 0){
                        if(window.execScript) {
                           window.execScript(match[2]);
                        } else {
                           window.eval(match[2]);
                        }
                    }
                }
                el = DOC.getElementById(id);
                if(el){Ext.removeNode(el);}
                if(Ext.isFunction(callback)){
                    callback();
                }
            });
            dom.innerHTML = html.replace(/(?:)((\n|\r|.)*?)(?:<\/script>)/ig, "");
            return this;
        },

        /**
         * Creates a proxy element of this element
         * @param {String/Object} config The class name of the proxy element or a DomHelper config object
         * @param {String/HTMLElement} renderTo (optional) The element or element id to render the proxy to (defaults to document.body)
         * @param {Boolean} matchBox (optional) True to align and size the proxy to this element now (defaults to false)
         * @return {Ext.Element} The new proxy element
         */
        createProxy : function(config, renderTo, matchBox){
            config = Ext.isObject(config) ? config : {tag : "div", cls: config};

            var me = this,
            	proxy = renderTo ? Ext.DomHelper.append(renderTo, config, true) :
            					   Ext.DomHelper.insertBefore(me.dom, config, true);

            if(matchBox && me.setBox && me.getBox){ // check to make sure Element.position.js is loaded
               proxy.setBox(me.getBox());
            }
            return proxy;
        }
    });

    Ext.Element.prototype.getUpdateManager = Ext.Element.prototype.getUpdater;

    // private
    Ext.Element.uncache = function(el){
        for(var i = 0, a = arguments, len = a.length; i < len; i++) {
            if(a[i]){
                delete Ext.Element.cache[a[i].id || a[i]];
            }
        }
    };