JavaScript 跨浏览器事件处理程序详解

<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>跨浏览器的事件处理程序</title>
</head>
<body>
  <input type="button" value="click me" id="myBtn"/>
  <input type="button" value="解除" id="unlisten"/>
 
  <script>
 
    function $(id){
      return document.getElementById(id);
    }
 
    var EventUtil={
      fnCount:0
      ,fnData:{}
      ,addHandler:function(element,type,handler){
        this.fnCount++;
        handler.fid = this.fnCount;
        var _fn = handler;
        handler = function(){
          _fn.call(element);
        };
        this.fnData[this.fnCount] = handler;
 
        if(element.addEventListener){
          element.addEventListener(type,handler,false);
        }  else if(element.attachEvent){
          element.attachEvent("on"+type,handler);
        }  else {
          element["on"+type]=handler;
        }
      }
      ,removeHandler:function(element,type,handler){
        handler = this.fnData[handler.fid];
        if(element.removeEventListener){
            element.removeEventListener(type,handler,false);
        }else if(element.detachEvent){
            element.detachEvent("on"+type,handler);
        }else{
            element["on"+type]=null;
        }
      }
    }
 
    var btn=$("myBtn");
    var unbtn = $('unlisten');
    var bindFn1=function(){
      alert(this.id);
    };
    var bindFn2=function(){
      alert('2');
    };
 
    EventUtil.addHandler(btn,"click",bindFn1);
    EventUtil.addHandler(btn,"click",bindFn2);
    //EventUtil.removeHandler(btn,"click",bindFn1);
    EventUtil.addHandler(unbtn,"click",function(){
      EventUtil.removeHandler(btn,"click",bindFn1);
    });
 
 
  </script>
</body>
</html>