函数绑定

var func1 = function(){
    if(this === window){
        console.log("this is window")
    }else{
        console.log("this is " + this)
    }
}
func1();
        

执行func1输出 : "this is window"

使用bind方法改变func1的this对象

var func2 = func1.bind("new");
func2()
        

执行func2输出 :"this is new"