js面向对象之继承-原型继承

//animal 父类 超类
        var Animal = function(name)
        {
            this.name = name;
            this.sayhello = function()
            {
                alert("HI，我是" + this.name + "，你愿意和我做朋友吗？");
            };
        };
        Animal.prototype.shout = function()
        {
            alert(this.name + "，正在叫！");
        };
        Animal.prototype.game = function()
        {
            alert(this.name + "，正在玩耍！");
        };
        
        var Dog = function(name)
        {
            //this.name = name;
            this.name = name;
            this.shout = function()//重写父类的函数
            {
                alert(this.name + "，正在汪汪叫！");
            };
        };
        
        var Cat = function(name)
        {
            this.name = name;
            this.shout = function()
            {
                alert(this.name + "，正在喵喵叫！");
            };
        };
        
        //原型继承
        Dog.prototype = Cat.prototype = new Animal();
        
        var xh = new Dog("小黑");
        xh.sayhello();
        xh.shout();
        xh.game();
        
        var xm = new Cat("小咪");
        xm.sayhello();
        xm.shout();
        xm.game();

 封装一个函数后：

var inherit = function (subclass, superclass) {
    subclass.prototype = new superclass();
};
 
//animal 父类 超类
var Animal = function (name) {
    this.name = name;
    this.sayhello = function () {
        alert("HI，我是" + this.name + "，你愿意和我做朋友吗？");
    };
};
Animal.prototype.shout = function () {
    alert(this.name + "，正在叫！");
};
Animal.prototype.game = function () {
    alert(this.name + "，正在玩耍！");
};
 
var Dog = function (name) {
    //this.name = name;
    this.name = name;
    this.shout = function () //重写父类的函数
    {
        alert(this.name + "，正在汪汪叫！");
    };
};
 
var Cat = function (name) {
    this.name = name;
    this.shout = function () {
        alert(this.name + "，正在喵喵叫！");
    };
};
 
//原型继承
//Dog.prototype = Cat.prototype = new Animal();
inherit(Dog, Animal);
inherit(Cat, Animal);
 
var xh = new Dog("小黑");
xh.sayhello();
xh.shout();
xh.game();
 
var xm = new Cat("小咪");
xm.sayhello();
xm.shout();
xm.game();

给函数添加extends方法

Function.prototype.extends = function (superclass) {
    this.prototype = new superclass();
};
 
//animal 父类 超类
var Animal = function (name) {
    this.name = name;
    this.sayhello = function () {
        alert("HI，我是" + this.name + "，你愿意和我做朋友吗？");
    };
};
Animal.prototype.shout = function () {
    alert(this.name + "，正在叫！");
};
Animal.prototype.game = function () {
    alert(this.name + "，正在玩耍！");
};
 
var Dog = function (name) {
    this.name = name;
    this.shout = function () //重写父类的函数
    {
        alert(this.name + "，正在汪汪叫，叫的很开心！");
    };
};
Dog.extends(Animal);
 
var Cat = function (name) {
    this.name = name;
    this.shout = function () {
        alert(this.name + "，正在喵喵叫！");
    };
};
Cat.extends(Animal);
 
//原型继承
//Dog.prototype = Cat.prototype = new Animal();
/*inherit(Dog, Animal);
        inherit(Cat, Animal);*/
//Dog.extends(Animal);
//Cat.extends(Animal);
 
/*var xh = new Dog("小黑");
        xh.sayhello();
        xh.shout();
        xh.game();
         
        var xm = new Cat("小咪");
        xm.sayhello();
        xm.shout();
        xm.game();*/
 
var Husky = function (name, color, sex) {
    this.name = name;
    this.color = color;
    this.sex = sex;
    this.sayhello = function () {
        alert("Hello，我是一条小" + this.sex + "狗，有一个非常好听的名字，叫：“" + this.name + "”，你愿意和我做朋友吗？");
    };
    this.showcolor = function () {
        alert(this.color);
    };
    /*this.shout = function()//重写父类的函数
            {
                alert(this.name + "，哼哼叫！");
            };*/
};
Husky.extends(Dog);
 
var xh = new Husky("小哈", "黑白", "公");
xh.sayhello();
xh.shout();
xh.game();
xh.showcolor();