跨浏览器的事件对象

var EventUtil = {
	
	addHandler : function(element, type, handler) {
		if (element.addEventListener) {
			element.addEventListener(type, handler, false);
		} else if (element.attachEvent) {
			element.attachEvent("on" + type, handler);
		} else {
			element["on" + type] = handler;
		}
	},
	
	getEvent : function(event) {
		return event ? event : window.event;
	},

	getTarget : function(event) {
		return event.target || event.srcElement;
	},

	preeventDefault : function(event) {
		if (event.preventDefault()) {
			event.preventDefault();
		} else {
			event.returnValue = false;
		}	
	},

	removeHandler : function(element, type, handler) {
		if (element.removeEventListener) {
			element.removeEventListener(type, handler, false);
		} else if (element.detachEvent) {
			element.detachEvent("on" + type, handler);
		} else {
			element["on" + type] = null;
		}
	},

	stopPropagation : function(event) {
		if (event.stopPropagation) {
			event.stopPropagation();
		} else {
			event.cancelBubble = true;
		}
	}
};