function Animal(){}
Animal.prototype={
    name:"animal",
    toString:function(){
        console.log(this.name);
    }
};
Animal.prototype.constructor=Animal;
function Dog(){}
//用于打破对象的引用传递,防止修改子类属性对父类产生影响
var F=function(){}
F.prototype=Animal.prototype
Dog.prototype=new F();
Dog.prototype.constructor=Dog;
Dog.prototype.name="dog";
var d=new Dog();
d.toString(); //打印子类name dog
var a=new Animal();
a.toString();//打印父类name animal

function Animal(){}
Animal.prototype={
    name:"animal",
    toString:function(){
        console.log(this.name);
    }
};
Animal.prototype.constructor=Animal;
function Dog(){}
//用于打破对象的引用传递,防止修改子类属性对父类产生影响
var F=function(){}
F.prototype=Animal.prototype
Dog.prototype=new F();
Dog.prototype.constructor=Dog;
Dog.prototype.name="dog";
Dog.uber=Animal.prototype;
var d=new Dog();
d.toString(); //打印子类name dog
//var a=new Animal();
//a.toString();//打印父类name animal

/**
 * Dog.prototype.constructor===d.constructor
 */
Dog.prototype.constructor.uber.toString();//打印animal（方式1）
d.constructor.uber.toString(); //打印animal（方式2）