继承

老版继承

call ()

function User(name, pass){
    this.name=name;
    this.pass=pass;
}
User.prototype.showName=function (){
    alert(this.name);
};
User.prototype.showPass=function (){
    alert(this.pass);
};
//继承
function VipUser(name, pass, level){
    User.call(this, name, pass);
    this.level=level;
}
VipUser.prototype=new User();
VipUser.prototype.constructor=VipUser;

VipUser.prototype.showLevel=function (){
    alert(this.level);
};

var v1=new VipUser('blue', '123456', 3);
v1.showName();
v1.showPass();
v1.showLevel();

ES6继承

extends 继承
super 超类/父类

class User{
    constructor(name, pass){
        this.name=name;
        this.pass=pass;
    }
    showName(){
        alert(this.name);
    }
    showPass(){
        alert(this.pass);
    }
}
//继承
class VipUser extends User{
    constructor(name, pass, level){
        super(name, pass);  //super(...args);
        this.level=level;
    }
    showLevel(){
        alert(this.level);
    }
}


var v1=new VipUser('blue', '123456', 3);
v1.showName();
v1.showPass();
v1.showLevel();