原型链

 //父亲
  function Father(name) {
   this.fatherName = name;
  }
  Father.prototype.age = 18;

  var ft = new Father("父亲");
  console.info(ft.age);
  console.info(ft.fatherName);

  //儿子
  function Son(name) {
   this.sonName = name;
  }
  Son.prototype = new Father();

  //每一个对象的_proto_都来自于构造函数的prototype属性
  var sn = new Son("儿子");
  console.info(sn.age);
  console.info(sn);

转载于:https://www.cnblogs.com/wangshuaiF26/p/5551262.html