關於js中函數裏的this

<script>
var user="window";

var obj={

user:"obj",
getUser0:function()
{
	alert(this);
	alert(this.user);
},
getUser1:function()
{
	alert(this);
	alert(user);
},
getUser2:function()
{
	return function(){
		alert(this);
		alert(this.user);
		
		}
	}

};

obj.getUser0();//輸出obj,obj
obj.getUser1();//輸出obj，輸出window
obj.getUser2()();//輸出window,window
obj.getUser2().call(obj);//輸出obj，obj

</script>

上述代碼在Firefox35.01中的輸出依次截圖如下：

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