JavaScript多态

function Master(){
        //给动物喂食
        this.feed=function(animal,food){
            window.alert(animal.constructor);
            document.writeln("主人给"+animal.name+" 喂"+food.name);
        }
    }

    //写食物
    function Food(name){
        this.name=name;
        //...
    }

    function Fish(name){
        this.food=Food;
        this.food(name);
    }

    function Bone(name){
        this.food=Food;
        this.food(name);
    }
    function Peach(name){
        this.food=Food;
        this.food(name);
    }
        //动物
    function Animal(name){
        this.name=name;
        //...
    }

    function Cat(name){
        this.animal=Animal;//对象冒充
        this.animal(name);
    }

    function Dog(name){
        this.animal=Animal;
        this.animal(name);
    }

    function Monkey(name){
        this.animal=Animal;
        this.animal(name);
    }

    var cat=new Cat("小猫咪");
    var dog=new Dog("小狗");
    var fish=new Fish("小鱼");
    var bone=new Bone("骨头");

    var master=new Master();
    master.feed(cat,fish);
    master.feed(dog,bone);
    master.feed(new Monkey("小猴"), new Peach("水蜜桃"));

运行结果：