js实现继承

js作为一种弱类型语言，继承也是其较大的功能之一

首先定义一个父类

// 定义一个教师类function Teacher (name) { ?// 属性 ?this.name = name || ‘Jack‘; ?// 实例方法 ?this.study= function(){ ???console.log(this.name + ‘正在学习！‘); ?}}

一：继承的方式

1，原型链继承：将父类的实例作为子类的原型

function Student(){ }

Student.prototype = new Teacher();

Student.prototype.name = ‘john‘;

测试
var student = new Student();
console.log(student.name);

2,构造继承 (call,apply) 使用父类的构造函数来增强子类的实例，等同于复制父类的实例属性给子类

function Student(name) {
　　Teacher.call(this);
　　this.name = name || "Tom"
}

var student = new Student();
console.log(student.name);

3,实例继承：为父类实例增加新特性作为子类实例返回

function Student(name){ ?var instance = new Teacher(); ?instance.name = name || ‘Tom‘; ?return instance;}// 测试var student = new Student();console.log(student.name);

4，拷贝继承

function Student(name){ ?var teacher= new Teacher(); ?for(var p in teacher){ ???Student.prototype[p] = Teacher[p]; ?} ?Student.prototype.name = name || ‘Tom‘;}// 测试var student= new Student();console.log(student.name);

5，组合继承 ?（通过调用父类的构造，继承父类的属性并保留传参的优点，然后通过将父类实例作为子类原型，实现函数复用

function Student(name){ ?Teacher.call(this); ?this.name = name || ‘Tom‘;}Student.prototype = new Teacher();// 测试var student = new Student();console.log(student.name);

6,寄生组合继承    通过寄生方式，砍掉父类的实例属性，这样，在调用两次父类的构造的时候，就不会初始化两次实例方法/属性，避免的组合继承的缺点

function Student(name){ ?Teacher.call(this); ?this.name = name || ‘Tom‘;}(function(){ ?// 创建一个没有实例方法的类 ?var Super = function(){}; ?Super.prototype = Teacher.prototype; ?//将实例作为子类的原型 ?Student.prototype = new Super();})();// 测试var student = new Student();console.log(student.name);

js实现继承

原文地址：http://www.cnblogs.com/shmily-code/p/7808608.html