The source code

    /**
     * @class Ext.EventManager
     * Registers event handlers that want to receive a normalized EventObject instead of the standard browser event and provides
     * several useful events directly.
     * See {@link Ext.EventObject} for more details on normalized event objects.
     * @singleton
     */
    Ext.EventManager = function(){
        var docReadyEvent,
        	docReadyProcId,
        	docReadyState = false,
        	E = Ext.lib.Event,
        	D = Ext.lib.Dom,
        	DOC = document,
        	WINDOW = window,
        	IEDEFERED = "ie-deferred-loader",
        	DOMCONTENTLOADED = "DOMContentLoaded",
        	elHash = {},
        	propRe = /^(?:scope|delay|buffer|single|stopEvent|preventDefault|stopPropagation|normalized|args|delegate)$/;

        /// There is some jquery work around stuff here that isn't needed in Ext Core.
        function addListener(el, ename, fn, wrap, scope){
            var id = Ext.id(el),
            	es = elHash[id] = elHash[id] || {};

            (es[ename] = es[ename] || []).push([fn, wrap, scope]);
            E.on(el, ename, wrap);

            // this is a workaround for jQuery and should somehow be removed from Ext Core in the future
            // without breaking ExtJS.
            if(ename == "mousewheel" && el.addEventListener){ // workaround for jQuery
            	var args = ["DOMMouseScroll", wrap, false];
            	el.addEventListener.apply(el, args);
                E.on(window, 'unload', function(){
    	            el.removeEventListener.apply(el, args);
                });
            }
            if(ename == "mousedown" && el == document){ // fix stopped mousedowns on the document
                Ext.EventManager.stoppedMouseDownEvent.addListener(wrap);
            }
        };

        function fireDocReady(){
            if(!docReadyState){
                Ext.isReady = docReadyState = true;
                if(docReadyProcId){
                    clearInterval(docReadyProcId);
                }
                if(Ext.isGecko || Ext.isOpera) {
                    DOC.removeEventListener(DOMCONTENTLOADED, fireDocReady, false);
                }
                if(Ext.isIE){
                    var defer = DOC.getElementById(IEDEFERED);
                    if(defer){
                        defer.onreadystatechange = null;
                        defer.parentNode.removeChild(defer);
                    }
                }
                if(docReadyEvent){
                    docReadyEvent.fire();
                    docReadyEvent.clearListeners();
                }
            }
        };

        function initDocReady(){
    	    var COMPLETE = "complete";

            docReadyEvent = new Ext.util.Event();
            if (Ext.isGecko || Ext.isOpera) {
                DOC.addEventListener(DOMCONTENTLOADED, fireDocReady, false);
            } else if (Ext.isIE){
                DOC.write("");
                DOC.getElementById(IEDEFERED).onreadystatechange = function(){
                    if(this.readyState == COMPLETE){
                        fireDocReady();
                    }
                };
            } else if (Ext.isWebKit){
                docReadyProcId = setInterval(function(){
                    if(DOC.readyState == COMPLETE) {
                        fireDocReady();
                     }
                }, 10);
            }
            // no matter what, make sure it fires on load
            E.on(WINDOW, "load", fireDocReady);
        };

        function createTargeted(h, o){
            return function(){
    	        var args = Ext.toArray(arguments);
                if(o.target == Ext.EventObject.setEvent(args[0]).target){
                    h.apply(this, args);
                }
            };
        };

        function createBuffered(h, o){
            var task = new Ext.util.DelayedTask(h);
            return function(e){
                // create new event object impl so new events don't wipe out properties
                task.delay(o.buffer, h, null, [new Ext.EventObjectImpl(e)]);
            };
        };

        function createSingle(h, el, ename, fn, scope){
            return function(e){
                Ext.EventManager.removeListener(el, ename, fn, scope);
                h(e);
            };
        };

        function createDelayed(h, o){
            return function(e){
                // create new event object impl so new events don't wipe out properties
                e = new Ext.EventObjectImpl(e);
                setTimeout(function(){
                    h(e);
                }, o.delay || 10);
            };
        };

        function listen(element, ename, opt, fn, scope){
            var o = !Ext.isObject(opt) ? {} : opt,
            	el = Ext.getDom(element);

            fn = fn || o.fn;
            scope = scope || o.scope;

            if(!el){
                throw "Error listening for \"" + ename + '\". Element "' + element + '" doesn\'t exist.';
            }
            function h(e){
                // prevent errors while unload occurring
                if(!Ext){// !window[xname]){  ==> can't we do this?
                    return;
                }
                e = Ext.EventObject.setEvent(e);
                var t;
                if (o.delegate) {
                    if(!(t = e.getTarget(o.delegate, el))){
                        return;
                    }
                } else {
                    t = e.target;
                }
                if (o.stopEvent) {
                    e.stopEvent();
                }
                if (o.preventDefault) {
                   e.preventDefault();
                }
                if (o.stopPropagation) {
                    e.stopPropagation();
                }
                if (o.normalized) {
                    e = e.browserEvent;
                }

                fn.call(scope || el, e, t, o);
            };
            if(o.target){
                h = createTargeted(h, o);
            }
            if(o.delay){
                h = createDelayed(h, o);
            }
            if(o.single){
                h = createSingle(h, el, ename, fn, scope);
            }
            if(o.buffer){
                h = createBuffered(h, o);
            }

            addListener(el, ename, fn, h, scope);
            return h;
        };

        var pub = {
    	    /**
    	     * Appends an event handler to an element.  The shorthand version {@link #on} is equivalent.  Typically you will
    	     * use {@link Ext.Element#addListener} directly on an Element in favor of calling this version.
    	     * @param {String/HTMLElement} el The html element or id to assign the event handler to
    	     * @param {String} eventName The type of event to listen for
    	     * @param {Function} handler The handler function the event invokes This function is passed
    	     * the following parameters:
    	     * evt : EventObjectThe {@link Ext.EventObject EventObject} describing the event.
    	     * t : ElementThe {@link Ext.Element Element} which was the target of the event.
    	     * Note that this may be filtered by using the delegate option.
    	     * o : ObjectThe options object from the addListener call.
    	     *
    	     * @param {Object} scope (optional) The scope (this reference) in which the handler function is executed. Defaults to the Element.
    	     * @param {Object} options (optional) An object containing handler configuration properties.
    	     * This may contain any of the following properties:
    	     * scope : ObjectThe scope (this reference) in which the handler function is executed. Defaults to the Element.
    	     * delegate : StringA simple selector to filter the target or look for a descendant of the target
    	     * stopEvent : BooleanTrue to stop the event. That is stop propagation, and prevent the default action.
    	     * preventDefault : BooleanTrue to prevent the default action
    	     * stopPropagation : BooleanTrue to prevent event propagation
    	     * normalized : BooleanFalse to pass a browser event to the handler function instead of an Ext.EventObject
    	     * delay : NumberThe number of milliseconds to delay the invocation of the handler after te event fires.
    	     * single : BooleanTrue to add a handler to handle just the next firing of the event, and then remove itself.
    	     * buffer : NumberCauses the handler to be scheduled to run in an {@link Ext.util.DelayedTask} delayed
    	     * by the specified number of milliseconds. If the event fires again within that time, the original
    	     * handler is not invoked, but the new handler is scheduled in its place.
    	     * target : ElementOnly call the handler if the event was fired on the target Element, not if the event was bubbled up from a child node.
    	     *

    	     * See {@link Ext.Element#addListener} for examples of how to use these options.
    	     */
    		addListener : function(element, eventName, fn, scope, options){
                if(Ext.isObject(eventName)){
    	            var o = eventName, e, val;
                    for(e in o){
    	                val = o[e];
                        if(!propRe.test(e)){
    	                    if(Ext.isFunction(val)){
    	                        // shared options
    	                        listen(element, e, o, val, o.scope);
    	                    }else{
    	                        // individual options
    	                        listen(element, e, val);
    	                    }
                        }
                    }
                } else {
                	listen(element, eventName, options, fn, scope);
            	}
            },

            /**
             * Removes an event handler from an element.  The shorthand version {@link #un} is equivalent.  Typically
             * you will use {@link Ext.Element#removeListener} directly on an Element in favor of calling this version.
             * @param {String/HTMLElement} el The id or html element from which to remove the event
             * @param {String} eventName The type of event
             * @param {Function} fn The handler function to remove
             */
            removeListener : function(element, eventName, fn, scope){
                var el = Ext.getDom(element),
                    id = Ext.id(el),
            	    wrap;

    	        Ext.each((elHash[id] || {})[eventName], function (v,i,a) {
    			    if (Ext.isArray(v) && v[0] == fn && (!scope || v[2] == scope)) {
    			        E.un(el, eventName, wrap = v[1]);
    			        a.splice(i,1);
    			        return false;
    		        }
    	        });

                // jQuery workaround that should be removed from Ext Core
    	        if(eventName == "mousewheel" && el.addEventListener && wrap){
    	            el.removeEventListener("DOMMouseScroll", wrap, false);
    	        }

    	        if(eventName == "mousedown" && el == DOC && wrap){ // fix stopped mousedowns on the document
    	            Ext.EventManager.stoppedMouseDownEvent.removeListener(wrap);
    	        }
            },

            /**
             * Removes all event handers from an element.  Typically you will use {@link Ext.Element#removeAllListeners}
             * directly on an Element in favor of calling this version.
             * @param {String/HTMLElement} el The id or html element from which to remove the event
             */
            removeAll : function(el){
    	        var id = Ext.id(el = Ext.getDom(el)),
    				es = elHash[id],
    				ename;

    	        for(ename in es){
    	            if(es.hasOwnProperty(ename)){
    	                Ext.each(es[ename], function(v) {
    	                    E.un(el, ename, v.wrap);
    	                });
    	            }
    	        }
    	        elHash[id] = null;
            },

            /**
             * Fires when the document is ready (before onload and before images are loaded). Can be
             * accessed shorthanded as Ext.onReady().
             * @param {Function} fn The method the event invokes
             * @param {Object} scope (optional) An object that becomes the scope of the handler
             * @param {boolean} options (optional) An object containing standard {@link #addListener} options
             */
            onDocumentReady : function(fn, scope, options){
                if(docReadyState){ // if it already fired
                    docReadyEvent.addListener(fn, scope, options);
                    docReadyEvent.fire();
                    docReadyEvent.clearListeners();
                } else {
                    if(!docReadyEvent) initDocReady();
                    options = options || {};
    	            options.delay = options.delay || 1;
    	            docReadyEvent.addListener(fn, scope, options);
                }
            },

            elHash : elHash
        };
         /**
         * Appends an event handler to an element.  Shorthand for {@link #addListener}.
         * @param {String/HTMLElement} el The html element or id to assign the event handler to
         * @param {String} eventName The type of event to listen for
         * @param {Function} handler The handler function the event invokes
         * @param {Object} scope (optional) The scope in which to execute the handler
         * function (the handler function's "this" context)
         * @param {Object} options (optional) An object containing standard {@link #addListener} options
         * @member Ext.EventManager
         * @method on
         */
        pub.on = pub.addListener;
        /**
         * Removes an event handler from an element.  Shorthand for {@link #removeListener}.
         * @param {String/HTMLElement} el The id or html element from which to remove the event
         * @param {String} eventName The type of event
         * @param {Function} fn The handler function to remove
         * @return {Boolean} True if a listener was actually removed, else false
         * @member Ext.EventManager
         * @method un
         */
        pub.un = pub.removeListener;

        pub.stoppedMouseDownEvent = new Ext.util.Event();
        return pub;
    }();
    /**
      * Fires when the document is ready (before onload and before images are loaded).  Shorthand of {@link Ext.EventManager#onDocumentReady}.
      * @param {Function} fn The method the event invokes
      * @param {Object} scope An object that becomes the scope of the handler
      * @param {boolean} options (optional) An object containing standard {@link #addListener} options
      * @member Ext
      * @method onReady
     */
    Ext.onReady = Ext.EventManager.onDocumentReady;

    //Initialize doc classes
    (function(){

        var initExtCss = function(){
            // find the body element
            var bd = document.body || document.getElementsByTagName('body')[0];
            if(!bd){ return false; }
            var cls = [' ',
                    Ext.isIE ? "ext-ie " + (Ext.isIE6 ? 'ext-ie6' : (Ext.isIE7 ? 'ext-ie7' : 'ext-ie8'))
                    : Ext.isGecko ? "ext-gecko " + (Ext.isGecko2 ? 'ext-gecko2' : 'ext-gecko3')
                    : Ext.isOpera ? "ext-opera"
                    : Ext.isWebKit ? "ext-webkit" : ""];

            if(Ext.isSafari){
                cls.push("ext-safari " + (Ext.isSafari2 ? 'ext-safari2' : (Ext.isSafari3 ? 'ext-safari3' : 'ext-safari4')));
            }else if(Ext.isChrome){
                cls.push("ext-chrome");
            }

            if(Ext.isMac){
                cls.push("ext-mac");
            }
            if(Ext.isLinux){
                cls.push("ext-linux");
            }

            if(Ext.isStrict || Ext.isBorderBox){ // add to the parent to allow for selectors like ".ext-strict .ext-ie"
                var p = bd.parentNode;
                if(p){
                    p.className += Ext.isStrict ? ' ext-strict' : ' ext-border-box';
                }
            }
            bd.className += cls.join(' ');
            return true;
        }

        if(!initExtCss()){
            Ext.onReady(initExtCss);
        }
    })();

    /**
     * @class Ext.EventObject
     * Just as {@link Ext.Element} wraps around a native DOM node, Ext.EventObject
     * wraps the browser's native event-object normalizing cross-browser differences,
     * such as which mouse button is clicked, keys pressed, mechanisms to stop
     * event-propagation along with a method to prevent default actions from taking place.
     * For example:
     *
    function handleClick(e, t){ // e is not a standard event object, it is a Ext.EventObject
        e.preventDefault();
        var target = e.getTarget(); // same as t (the target HTMLElement)
        ...
    }
    var myDiv = {@link Ext#get Ext.get}("myDiv");  // get reference to an {@link Ext.Element}
    myDiv.on(         // 'on' is shorthand for addListener
        "click",      // perform an action on click of myDiv
        handleClick   // reference to the action handler
    );
    // other methods to do the same:
    Ext.EventManager.on("myDiv", 'click', handleClick);
    Ext.EventManager.addListener("myDiv", 'click', handleClick);

     * @singleton
     */
    Ext.EventObject = function(){
        var E = Ext.lib.Event,
        	// safari keypress events for special keys return bad keycodes
        	safariKeys = {
    	        3 : 13, // enter
    	        63234 : 37, // left
    	        63235 : 39, // right
    	        63232 : 38, // up
    	        63233 : 40, // down
    	        63276 : 33, // page up
    	        63277 : 34, // page down
    	        63272 : 46, // delete
    	        63273 : 36, // home
    	        63275 : 35  // end
        	},
        	// normalize button clicks
        	btnMap = Ext.isIE ? {1:0,4:1,2:2} :
                    (Ext.isWebKit ? {1:0,2:1,3:2} : {0:0,1:1,2:2});

        Ext.EventObjectImpl = function(e){
            if(e){
                this.setEvent(e.browserEvent || e);
            }
        };

        Ext.EventObjectImpl.prototype = {
               /** @private */
            setEvent : function(e){
    	        var me = this;
                if(e == me || (e && e.browserEvent)){ // already wrapped
                    return e;
                }
                me.browserEvent = e;
                if(e){
                    // normalize buttons
                    me.button = e.button ? btnMap[e.button] : (e.which ? e.which - 1 : -1);
                    if(e.type == 'click' && me.button == -1){
                        me.button = 0;
                    }
                    me.type = e.type;
                    me.shiftKey = e.shiftKey;
                    // mac metaKey behaves like ctrlKey
                    me.ctrlKey = e.ctrlKey || e.metaKey || false;
                    me.altKey = e.altKey;
                    // in getKey these will be normalized for the mac
                    me.keyCode = e.keyCode;
                    me.charCode = e.charCode;
                    // cache the target for the delayed and or buffered events
                    me.target = E.getTarget(e);
                    // same for XY
                    me.xy = E.getXY(e);
                }else{
                    me.button = -1;
                    me.shiftKey = false;
                    me.ctrlKey = false;
                    me.altKey = false;
                    me.keyCode = 0;
                    me.charCode = 0;
                    me.target = null;
                    me.xy = [0, 0];
                }
                return me;
            },

            /**
             * Stop the event (preventDefault and stopPropagation)
             */
            stopEvent : function(){
    	        var me = this;
                if(me.browserEvent){
                    if(me.browserEvent.type == 'mousedown'){
                        Ext.EventManager.stoppedMouseDownEvent.fire(me);
                    }
                    E.stopEvent(me.browserEvent);
                }
            },

            /**
             * Prevents the browsers default handling of the event.
             */
            preventDefault : function(){
                if(this.browserEvent){
                    E.preventDefault(this.browserEvent);
                }
            },

            /**
             * Cancels bubbling of the event.
             */
            stopPropagation : function(){
    	        var me = this;
                if(me.browserEvent){
                    if(me.browserEvent.type == 'mousedown'){
                        Ext.EventManager.stoppedMouseDownEvent.fire(me);
                    }
                    E.stopPropagation(me.browserEvent);
                }
            },

            /**
             * Gets the character code for the event.
             * @return {Number}
             */
            getCharCode : function(){
                return this.charCode || this.keyCode;
            },

            /**
             * Returns a normalized keyCode for the event.
             * @return {Number} The key code
             */
            getKey : function(){
                return this.normalizeKey(this.keyCode || this.charCode)
            },

    		// private
    		normalizeKey: function(k){
    			return Ext.isSafari ? (safariKeys[k] || k) : k;
    		},

            /**
             * Gets the x coordinate of the event.
             * @return {Number}
             */
            getPageX : function(){
                return this.xy[0];
            },

            /**
             * Gets the y coordinate of the event.
             * @return {Number}
             */
            getPageY : function(){
                return this.xy[1];
            },

            /**
             * Gets the page coordinates of the event.
             * @return {Array} The xy values like [x, y]
             */
            getXY : function(){
                return this.xy;
            },

            /**
             * Gets the target for the event.
             * @param {String} selector (optional) A simple selector to filter the target or look for an ancestor of the target
             * @param {Number/Mixed} maxDepth (optional) The max depth to
                    search as a number or element (defaults to 10 || document.body)
             * @param {Boolean} returnEl (optional) True to return a Ext.Element object instead of DOM node
             * @return {HTMLelement}
             */
            getTarget : function(selector, maxDepth, returnEl){
                return selector ? Ext.fly(this.target).findParent(selector, maxDepth, returnEl) : (returnEl ? Ext.get(this.target) : this.target);
            },

            /**
             * Gets the related target.
             * @return {HTMLElement}
             */
            getRelatedTarget : function(){
                return this.browserEvent ? E.getRelatedTarget(this.browserEvent) : null;
            },

            /**
             * Normalizes mouse wheel delta across browsers
             * @return {Number} The delta
             */
            getWheelDelta : function(){
                var e = this.browserEvent;
                var delta = 0;
                if(e.wheelDelta){ /* IE/Opera. */
                    delta = e.wheelDelta/120;
                }else if(e.detail){ /* Mozilla case. */
                    delta = -e.detail/3;
                }
                return delta;
            },

    		/**
    		* Returns true if the target of this event is a child of el.  Unless the allowEl parameter is set, it will return false if if the target is el.
    		* Example usage:
    		// Handle click on any child of an element
    		Ext.getBody().on('click', function(e){
    			if(e.within('some-el')){
    				alert('Clicked on a child of some-el!');
    			}
    		});

    		// Handle click directly on an element, ignoring clicks on child nodes
    		Ext.getBody().on('click', function(e,t){
    			if((t.id == 'some-el') && !e.within(t, true)){
    				alert('Clicked directly on some-el!');
    			}
    		});

    		 * @param {Mixed} el The id, DOM element or Ext.Element to check
    		 * @param {Boolean} related (optional) true to test if the related target is within el instead of the target
    		 * @param {Boolean} allowEl {optional} true to also check if the passed element is the target or related target
    		 * @return {Boolean}
    		 */
    		within : function(el, related, allowEl){
                if(el){
    			    var t = this[related ? "getRelatedTarget" : "getTarget"]();
    			    return t && ((allowEl ? (t == Ext.getDom(el)) : false) || Ext.fly(el).contains(t));
                }
                return false;
    		}
    	 };

        return new Ext.EventObjectImpl();
    }();