前言：大多OO语言都支持两种继承方式：接口继承和实现继承，而ECMAScript中无法实现接口继承，ECMAScript只支持实现继承，而且其实现继承主要是依靠原型链来实现。

1.原型链

基本思想：利用原型让一个引用类型继承另外一个引用类型的属性和方法。

原型链实现继承例子：

function SuperType() {    this.property = true;}SuperType.prototype.getSuperValue = function() {    return this.property;}function subType() {    this.property = false;}//继承了SuperTypeSubType.prototype = new SuperType();SubType.prototype.getSubValue = function (){    return this.property;}var instance = new SubType();console.log(instance.getSuperValue());//true

2.借用构造函数

基本思想：在子类型构造函数的内部调用超类构造函数，通过使用call()和apply()方法可以在新创建的对象上执行构造函数。

例子：

function SuperType() {    this.colors = ["red","blue","green"];}function SubType() {    SuperType.call(this);//继承了SuperType}var instance1 = new SubType();instance1.colors.push("black");console.log(instance1.colors);//"red","blue","green","black"var instance2 = new SubType();console.log(instance2.colors);//"red","blue","green"

3.组合继承

基本思想：将原型链和借用构造函数的技术组合在一块，从而发挥两者之长的一种继承模式。

例子：

function SuperType(name) {    this.name = name;    this.colors = ["red","blue","green"];}SuperType.prototype.sayName = function() {    console.log(this.name);}function SubType(name, age) {    SuperType.call(this,name);//继承属性    this.age = age;}//继承方法SubType.prototype = new SuperType();Subtype.prototype.constructor = Subtype;Subtype.prototype.sayAge = function() {    console.log(this.age);}var instance1 = new SubType("EvanChen",18);instance1.colors.push("black");consol.log(instance1.colors);//"red","blue","green","black"instance1.sayName();//"EvanChen"instance1.sayAge();//18var instance2 = new SubType("EvanChen666",20);console.log(instance2.colors);//"red","blue","green"instance2.sayName();//"EvanChen666"instance2.sayAge();//20

4.原型式继承

基本想法：借助原型可以基于已有的对象创建新对象，同时还不必须因此创建自定义的类型。

原型式继承的思想可用以下函数来说明：

function object(o) {    function F(){}    F.prototype = o;    return new F();}

例子：

var person = {    name:"EvanChen",    friends:["Shelby","Court","Van"];};var anotherPerson = object(person);anotherPerson.name = "Greg";anotherPerson.friends.push("Rob");var yetAnotherPerson = object(person);yetAnotherPerson.name = "Linda";yetAnotherPerson.friends.push("Barbie");console.log(person.friends);//"Shelby","Court","Van","Rob","Barbie"

ECMAScript5通过新增Object.create()方法规范化了原型式继承，这个方法接收两个参数：一个用作新对象原型的对象和一个作为新对象定义额外属性的对象。

var person = {    name:"EvanChen",    friends:["Shelby","Court","Van"];};var anotherPerson = Object.create(person);anotherPerson.name = "Greg";anotherPerson.friends.push("Rob");var yetAnotherPerson = Object.create(person);yetAnotherPerson.name = "Linda";yetAnotherPerson.friends.push("Barbie");console.log(person.friends);//"Shelby","Court","Van","Rob","Barbie"

5.寄生式继承

基本思想：创建一个仅用于封装继承过程的函数，该函数在内部以某种方式来增强对象，最后再像真正是它做了所有工作一样返回对象。

例子：

function createAnother(original) {    var clone = object(original);    clone.sayHi = function () {        alert("hi");    };    return clone;}var person = {    name:"EvanChen",    friends:["Shelby","Court","Van"];};var anotherPerson = createAnother(person);anotherPerson.sayHi();///"hi"

6.寄生组合式继承

基本思想：通过借用函数来继承属性，通过原型链的混成形式来继承方法

function inheritProperty(subType, superType) {    var prototype = object(superType.prototype);//创建对象    prototype.constructor = subType;//增强对象    subType.prototype = prototype;//指定对象}

例子：

function SuperType(name){    this.name = name;    this.colors = ["red","blue","green"];}SuperType.prototype.sayName = function (){    alert(this.name);};function SubType(name,age){    SuperType.call(this,name);    this.age = age;}inheritProperty(SubType,SuperType);SubType.prototype.sayAge = function() {    alert(this.age);}