6.继承

6.1 Javascript的继承是基于原型的继承

6.1.1属性的继承

                 function Person(name,age){
            this.name=name;
            this.age=age;
        }
        function Teacher(name,age,skill){
            Person.call(this,name,age)//Person(name,age)中的this指向window,需要改变this指向
            this.skill=skill;//this指向 Teacher构造函数的实例对象
        }
                var t=new Teacher("meng",21,"js");
                consloe.log(t)

6.1.2 方法的继承

                 function Person(name,age){
            this.name=name;
            this.age=age;
        }
        Person.prototype.sayName=function(){
            console.log(this.name)
        }
        function Teacher(name,age,skill){
            Person.call(this,name,age)
            this.skill=skill;
        }
        Teacher.prototype=Person.prototype;//因为Teacher要使用Person里的sayName方法，把Person的原型赋给Teacher
        Teacher.prototype.sayName=function(){
            console.log(this.age)
        }
        Teacher.prototype.constructor=Teacher;//line12 因为把Person赋给了Teacher，所以Teacher的构造属性(constructor)也变成了Person的构造属性
        var t=new Teacher("meng",21,"js");
        var p=new Person("name",19)
        console.log(t)

es5方法

                function Person(name,age){
            this.name=name;
            this.age=age;
        }
        Person.prototype.sayName=function(){
            console.log(this.name)
        }
        function Teacher(name,age,skill){
            Person.call(this,name,age)
            this.skill=skill;
        }
        Teacher.prototype=Object.create(Person.prototype,{
            constructor:{
                value:Teacher
            }
        })
        Teacher.prototype.sayAge=function(){
            console.log(this.age)
        }
        var t=new Teacher("meng",21,"js")
        console.log(t.constructor)
        t.sayName();
        t.sayAge();