JS高级---逆推继承看原型

逆推继承看原型

 

 

 

    function f1(age) {
      this.age = age;
    }
    function f2(age) {
      this.age = age;
    }
    f2.prototype = new f1(10);
    function f3(age) {
      this.age = age;
    }
    f3.prototype = new f2(20);

    var f3 = new f3(30);
    console.log(f3.age);//