继承

继承发展史

1.传统形式-->原型链

Father.prototype.lastName="小明";
           function Father(){};
           Son.prototype=new Father();
           function Son (){};
           var son=new Son();

  过多的继承了没用的属性(全部继承下来)

2.借用构造函数

Father.prototype.lastName="小明";
            function Father(ko){
                this.mm=ko;
            };
            function Son (){Father.call(this,"消防")};
            var son=new Son();

  不能继承借用构造函数的原型
  每次构造函数都要都走一个函数

3.共享原型

Father.prototype.lastName="小明";
            function Father(){};
            Son.prototype=Father.prototype;
            function Son(){};
            var son =new Son();
            var father=new Father();

不能随便改动自己的原型

4.圣杯模式(就比上面多添加了F)

// Father.prototype
            //
            //                          function F(){}
            //                          F.prototype=Father.protopyte
            //                          Son.prototype=new F();
            //Father                       Son 
            //圣杯模式
            function inherit(Target,Origin){
                function F(){};
                F.prototype=Origin.prototype;
                Target.prototype=new F();
                Target.prototype.constuctor=Target;
                Target.prototype.uber=Origin.prototype;
            }
            Father.prototype.lastName="小米功能";
            function Father(){
                
            }
            function Son(){
                
            }
            inherit(Son,Father);
            var son=new Son();
            var father=new Father();
            son.__proto__-->new F().__proto__-->Fanher.prototype

即使被new了F里面也没有什么东西可运行的,除了原型,所以他是最终的模型

var inhert=(function (){
                 var F=function(){};
                 return function (Targer,Origin){
                     F.prototype=Origin.prototype;
                     Targer.prototype=new F();
                     Targer.prototype.constructor=Targer;
                     Targer.prototype.uber=Origin.prototype;
                 }
             }());
             inhert(Son,Father);
             Father.prototype.lastName="小爱好";
             function Father(){
             }
             function Son(){}
             var son=new Son();

练习

 function inherit(Target,Origin){
                function F(){};
                F.prototype=Origin.prototype;
                Target.prototype=new F();
                Target.prototype.constuctor=Target;
                Target.prototype.uber=Origin.prototype;
            }
            Father.prototype.lastName="小米功能";
            function Father(){}
            function Son(){
                
            }
            inherit(Son,Father);
            var son=new Son();
            var father=new Father();
            
            var inhert1=(function (){
                 var F=function(){};
                 return function (Targer,Origin){
                     F.prototype=Origin.prototype;
                     Targer.prototype=new F();
                     Targer.prototype.constructor=Targer;
                     Targer.prototype.uber=Origin.prototype;
                 }
             }());
             inhert1(Son1,Father1);
             Father1.prototype.lastName="小爱好";
             function Father1(){
             }
             function Son1(){}
             var son1=new Son1();