class Father{

      constructor(a){
        console.log(a);
      }
      play(){
        console.log("aaa");
      }
      static run(){
        console.log("static");
      }
    }
    class Son extends Father{
      constructor(){
        super();
      }
    }
    var s=new Son();
    s.play();
    Father.run()
    Son.run();

function Father(_r){
      this.r=_r;
      console.log("aa");
      console.log(this.r);
    }
    Father.a=3;
    Father.run=function(){
      console.log(Box.a);
    }
function Son(){
      Father.call(this,3)；//改变this的指向，执行父类构造函数并传参到父类
    }
    var b=new Son();//"aa",3
    b.run();//TypeError

function Father(){
  console.log("aa");
    }
Father.prototype.b=10;
    Father.prototype.play=function(){
      console.log(this.b);
    }
    Son.prototype=new Father();
    function Son(){
    }
    var b=new Son();
    b.play();//10

function Father(_r){
      this.r=_r;
      console.log("aa");
    }
function Son(_r){
      Father.call(this,_r);//冒充，改变父类的this指向子类
    }
Son.prototype=new Father(3);//原型链继承
 var c=new Son(10);

function Father(_a){
      this.a=_a
    }
    Father.prototype.play=function(){
      console.log("aaa");
    }
      function Agent(){

      }
      Agent.prototype=Father.prototype;
      function Son(){

      }
      Son.prototype=new Agent();
      var o=new Son();
      o.play();//aaa

function extend(subClass, supClass) {
     function Agent() {}
     Agent.prototype = supClass.prototype;
     var o = subClass.prototype;
     subClass.prototype = new Agent();
     if (Object.assign) {
      Object.assign(subClass.prototype, o);
     } else {
      if (Object.getOwnPropertyNames) {
       var names = Object.getOwnPropertyNames(o);
       for (var i = 0; i < names.length; i++) {
        var desc = Object.getOwnPropertyDescriptor(names[i]);
        Object.defineProperty(subClass.prototype, names[i], desc);
       }
      } else {
       for (var prop in o) {
        subClass.prototype[prop] = o[prop];
       }
      }
     }
     subClass.prototype.constructor = subClass; //防止子类的构造函数被覆盖
     if (supClass.prototype.constructor === Object) {
      supClass.prototype.constructor = supClass; //防止父类类的构造函数被覆盖
     }
     // 存储父类，方便继承构造函数调用
     subClass.prototype.superClass = supClass;
    }
 //调用
    function Father(_r) {
     this.r = _r;
     console.log("Father");
    }
    Father.prototype.play = function () {
     console.log("play game");
    };
    function Ball(_r) {
     this.superClass.call(this, _r);
    }
    var s = new Son(10);//Father
    s.play();//play game