函数绑定(bind)

 1 function bind(fn, context) {
 2     return function() {
 3         return fn.apply(context, arguments);
 4     };
 5 }
 6 
 7 //使用方法
 8 var handler = {
 9     message: "Event handler",
10     handleClick: function() {
11         console.log(this.message + ":" + event.type);
12     }
13 };
14 var btn = document.getElementById("my-btn");
15 EventUtil.addHandler(btn, "click", bind(handler.handleClick, handler));