欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  IT编程

javascript面向对象中继承实现

程序员文章站 2022-06-26 09:37:07
面向对象的基本特征有:封闭、继承、多态。 在javascript中实现继承的方法: 1. 原型链(prototype chaining) 2. call()/apply()...

面向对象的基本特征有:封闭、继承、多态。

javascript中实现继承的方法:

1. 原型链(prototype chaining)

2. call()/apply()

3. 混合方式(prototype和call()/apply()结合)

4. 对象冒充

继承的方法如下:

1、prototype原型链方式:

[html]view plaincopy

functionteacher(name){ this.name=name; } teacher.prototype.sayname=function(){ console.log("nameis"+this.name); } varteacher1=newteacher("xiaoming"); teacher1.sayname(); functionstudent(name){ this.name=name; } student.prototype=newteacher() varstudent1=newstudent("xiaolan"); student1.sayname(); //nameisxiaoming //nameisxiaolan

2、call()/apply()方法

function teacher(name,age){

this.name = name;

this.age = age;

this.sayhi = function(){

alert('name:'+name+", age:"+age);

}

}

function student(){

var args = arguments;

teacher.call(this,args[0],args[1]);

// teacher.apply(this,arguments);

}

var teacher1 = new teacher('xiaoming',23);

teacher1.sayhi();

var student1 = new student('xiaolan',12);

student1.sayhi();

// alert: name:xiaoming, age:23

// alert: name:xiaolan, age:12

3、混合方法【prototype,call/apply】

function teacher(name,age){

this.name = name;

this.age = age;

}

teacher.prototype.sayname = function(){

console.log('name:'+this.name);

}

teacher.prototype.sayage = function(){

console.log('age:'+this.age);

}

function student(){

var args = arguments;

teacher.call(this,args[0],args[1]);

}

student.prototype = new teacher();

var student1 = new student('xiaolin',23);

student1.sayname();

student1.sayage();

// name:xiaolin

// age:23

4、对象冒充

function person(name,age){

this.name = name;

this.age = age;

this.show = function(){

console.log(this.name+", "+this.age);

}

}

function student(name,age){

this.student = person; //将person类的构造函数赋值给this.student

this.student(name,age); //js中实际上是通过对象冒充来实现继承的

delete this.student; //移除对person的引用

}

var s = new student("小明",17);

s.show();

var p = new person("小花",18);

p.show();

// 小明, 17

// 小花, 18