最近看ol2源码的时候发现的，懒事件，动态事件，就是对DOM element 附加事件的时候，动态改变eventHandle，实际就是用了js原型链及闭包的知识
<!Doctype html>
<html xmlns=http://www.w3.org/1999/xhtml>
<head>
<meta http-equiv=Content-Type content="text/html;charset=utf-8">
<meta http-equiv=X-UA-Compatible content="IE=edge,chrome=1">
<title></title>
</head>
<body>
<button id="btn">lazy event</button>
</body>
<script>
var clickHandle = function(){
alert(1);
}
var clickHandle2 = function(){
alert(2);
}
var CEvent = function(){
this.handle;
};
CEvent.prototype ={
setHandle : function(handle){
this.handle = handle;
},
attachHanlde : function(){
var self = this;
return function(event){
return self.handle.call(event || window.event);
};
}
}
var myEvent = new CEvent();
myEvent.setHandle(clickHandle);
document.getElementById("btn").addEventListener("click",myEvent.attachHanlde());
//document.getElementById("btn").addEventListener("click",myEvent.handle);
myEvent.setHandle(clickHandle2);
</script>
</html> 实例很简单，自己运行试试就知道了