原型链继承.md

初级

    function Parent(name){
        if(name){
            this.name = name;
        }
        else{
            this.nameless = true;
        }
    }

    Parent.prototype.sayName = function(){
        console.info(this.name);
    }

    Parent.prototype.hasName = function(){
        console.info(this.nameless?"无名":"有");
    }

    function Son(){
        Parent.apply(this,arguments);
        //other code
    }

    Son.prototype = Parent.prototype;
    Son.prototype.constructor = Son;

一般的继承方式

    function Parent(name){
        if(name){
            this.name = name;
        }
        else{
            this.nameless = true;
        }
    }

    Parent.prototype.sayName = function(){
        console.info(this.name);
    }

    Parent.prototype.hasName = function(){
        console.info(this.nameless?"无名":"有");
    }

    function Son(){
        Parent.apply(this,arguments);
        //other code
    }

    Son.prototype = new Parent();
    Son.prototype.constructor = Son;

    var man = new Son("张三");

    man.sayName();
    man.hasName();

一般继承方式的问题

解决方案

    function Parent(name){
        if(name){
            this.name = name;
        }
        else{
            this.nameless = true;
        }
    }

    Parent.prototype.sayName = function(){
        console.info(this.name);
    }

    Parent.prototype.hasName = function(){
        console.info(this.nameless?"无名":"有");
    }


    function Son(){
        Parent.apply(this,arguments);//在这调用父类构造函数构造该类成员变量。
    }

    function tempCtor() {}; //中间类
    tempCtor.prototype = Parent.prototype; //中间类继承父类的成员方法，而不继承父类的成员变量
    Son.prototype = new tempCtor();
    Son.prototype.constructor = Son;
    
    var man = new Son("张三");

    man.sayName();
    man.hasName();