用用匿名函数和闭包加apply强制待定函数调用时使用特定上下文

<button id="test">点我</button>
<script>
 var button={
     clicked:false,
     click:function(){
         debugger;
        this.clicked=true;
        console.assert(!(button.clicked),"The button has been clicked");
     }
 }
 var elem=document.getElementById("test");
 //error
 //elem.addEventListener("click",button.click,false);
 elem.addEventListener("click",bind(button,"click"),false);
 function bind(context,name){
     return function(){
      
        return context[name].apply(context,arguments);
     };
 }