javascript 跨浏览器事件对象、阻止默认事件、阻止冒泡兼容写法
var EventUtil = {
getEvent: function(event){
return event ? event : window.event;
},
getTarget: function(event){
return event.target || event.srcElement;
},
preventDefault: function(event){
if (event.preventDefault){
event.preventDefault();
} else {
event.returnValue = false;
}
stopPropagation: function(event){
if (event.stopPropagation){
event.stopPropagation();
} else {
event.cancelBubble = true;
}
}