兼容各大浏览器的event获取

event:

 //得到事件
 function getEvent(evt){

     if (evt && typeof(evt) != "undefined") {
         var e = window.event || arguments.callee.caller.arguments[0];

         if (typeof(evt) != "undefined") {
             e = window.event || evt;
         }

         return e;
     } else {
         if(window.event)    {return window.event;}

         try {
             func = getEvent.caller;

             while(func!=null){
                 var arg0=func.arguments[0];

                 if(arg0){
                     if((arg0.constructor==Event || arg0.constructor ==MouseEvent
                         || arg0.constructor==KeyboardEvent)
                         ||(typeof(arg0)=="object" && arg0.preventDefault
                         && arg0.stopPropagation)){
                         return arg0;
                     }
                 }

                 func = func.caller;
             }
         } catch (e) {
             return null;
         }

         return null;
     }
 }

target:

 //获取事件操作对象
 function getTarget(evt) {
     //var e = window.event || arguments.callee.caller.arguments[0]; //获取触发事件的源对象
     var e = getEvent(evt); //获取触发事件的源对象

     if (typeof(e) != "undefined") {
         try {
             var target =  (typeof(e.srcElement) != "undefined") && e.srcElement ? e.srcElement : e.target;
         } catch (ex) {
             target = null;
         }

     } else {
         target = null;
     }

     return target;
 }

事件冒泡:

//事件冒泡
function preventEvent() {
    //取消事件冒泡
    //var e = arguments.callee.caller.arguments[0] || event; //若省略此句，下面的e改为event，IE运行可以，但是其他浏览器就不兼容
    var e = getEvent(); //获取触发事件的源对象

    if (e && e.stopPropagation) {
        // this code is for Mozilla and Opera
        e.stopPropagation();
    } else if (window.event) {
        // this code is for IE
        window.event.cancelBubble = true;
    }
}