let foo = {
    something: function(){
        console.log("Tell me something good...")
    }
};
let bar = Object.create(foo);	//Object.create(..)会创建一个新对象（bar）并把它关联到我们指定的对象（foo）
bar.something()		//当something不存在bar，会把ta委托给foo

//利用[[Prototype]]把b1委托给Bar并把Bar委托给Foo，实现了三个对象之间的关联。
Foo = {
            init:function(who){
                this.me = who;
            },
            identify:function(){
                return "I am " + this.me
            }
        }
        Bar = Object.create(Foo);

        Bar.speak = function(){
            alert("Hello,"+ this.identify()+".")
        };

        var b1 = Object.create(Bar);
        b1.init("b1")
        var b2 = Object.create(Bar);
        b2.init("b2")

        b1.speak();
        b2.speak();