JavaScript对象的创建
JavaScript中定义对象的几种方式（JavaScript中没有类的概念，只有对象）：
1） 基于已有对象扩充其属性和方法：
[html] view plaincopy print?
var object = new Object(); object.name = "zhangsan"; object.sayName = function(name) { this.name = name; alert(this.name); } object.sayName("lisi");
2）工厂方式
[html] view plaincopy print?
//工厂方式创建对象 /* function createObject() { var object = new Object(); object.username = "zhangsan"; object.password = "123"; object.get = function() { alert(this.username + ", " + this.password); } return object; } var object1 = createObject(); var object2 = createObject(); object1.get();
带参数的构造方法：
[html] view plaincopy print?
function createObject(username, password) { var object = new Object(); object.username = username; object.password = password; object.get = function() { alert(this.username + ", " + this.password); } return object; } var object1 = createObject("zhangsan", "123"); object1.get();
让一个函数对象被多个对象所共享，而不是每一个对象拥有一个函数对象。
[html] view plaincopy print?
function get() { alert(this.username + ", " + this.password); } function createObject(username, password) { var object = new Object(); object.username = username; object.password = password; object.get = get; return object; } var object = createObject("zhangsan", "123"); var object2 = createObject("lisi", "456"); object.get(); object2.get();
3）构造函数方式
[html] view plaincopy print?
function Person() { //在执行第一行代码前，js引擎会为我们生成一个对象 this.username = "zhangsan"; this.password = "123"; this.getInfo = function() { alert(this.username + ", " + this.password); } //此处有一个隐藏的return语句，用于将之前生成的对象返回 } var person = new Person(); person.getInfo();
可以在构造对象时传递参数
[html] view plaincopy print?
function Person(username, password) { this.username = username; this.password = password; this.getInfo = function() { alert(this.username + ", " + this.password); } } var person = new Person("zhangsan", "123"); person.getInfo();
4）原型（“prototype”）方式
[html] view plaincopy print?
//使用原型（prototype）方式创建对象 /* function Person() { } Person.prototype.username = "zhangsan"; Person.prototype.password = "123"; Person.prototype.getInfo = function() { alert(this.username + ", " + this.password); } var person = new Person(); var person2 = new Person(); person.username = "lisi"; person.getInfo(); person2.getInfo(); */
[html] view plaincopy print?
function Person() { } Person.prototype.username = new Array(); Person.prototype.password = "123"; Person.prototype.getInfo = function() { alert(this.username + ", " + this.password); } var person = new Person(); var person2 = new Person(); person.username.push("zhangsan"); person.username.push("lisi"); person.password = "456"; person.getInfo(); person2.getInfo();
如果使用原型方式对象，那么生成的所有对象会共享原型中的属性，这样一个对象改变了该属性也会反应到其他对象当中。
单纯使用原型方式定义对象无法在构造函数中为属性赋初值，只能在对象生成后再去改变属性值。
使用原型+构造函数方式来定义对象，对象之间的属性互不干扰，各 个对象间共享同一个方法
[html] view plaincopy print?
//使用原型+构造函数方式来定义对象 function Person() { this.username = new Array(); this.password = "123"; } Person.prototype.getInfo = function() { alert(this.username + ", " + this.password); } var p = new Person(); var p2 = new Person(); p.username.push("zhangsan"); p2.username.push("lisi"); p.getInfo(); p2.getInfo();
5）动态原型方式：在构造函数中通过标志量让所有对象共享一个方法，而每个对象拥有自己的属性。
[html] view plaincopy print?
function Person() { this.username = "zhangsan"; this.password = "123"; if(typeof Person.flag == "undefined") { alert("invoked"); Person.prototype.getInfo = function() { alert(this.username + ", " + this.password); } Person.flag = true; } } var p = new Person(); var p2 = new Person(); p.getInfo(); p2.getInfo();
JavaScript中的继承。
1） 对象冒充
[html] view plaincopy print?
//继承第一种方式：对象冒充 function Parent(username) { this.username = username; this.sayHello = function() { alert(this.username); } } function Child(username, password) { //下面三行代码是最关键的代码 this.method = Parent; this.method(username); delete this.method; this.password = password; this.sayWorld = function() { alert(this.password); } } var parent = new Parent("zhangsan"); var child = new Child("lisi", "1234"); parent.sayHello(); child.sayHello(); child.sayWorld();
2） call方法方式。
call方法是Function对象中的方法，因此我们定义的每个函数都拥有该方法。可以通过函数名来调用call方法，call方法的第一个参数会被传递给函数中的this，从第2个参数开始，逐一赋值给函数中的参数。
[html] view plaincopy print?
<p>//使用call方式实现对象的继承</p><p>function Parent(username) { this.username = username;</p><p> this.sayHello = function() { alert(this.username); } }</p><p>function Child(username, password) { Parent.call(this, username);</p><p> this.password = password;</p><p> this.sayWorld = function() { alert(this.password); } }</p><p>var parent = new Parent("zhangsan");</p><p>var child = new Child("lisi", "123");</p><p>parent.sayHello();</p><p>child.sayHello(); child.sayWorld();</p><p> </p><span style="font-size:18px;"><span style="color:#000000;"> </span></span>
3） apply方法方式
[html] view plaincopy print?
//使用apply方法实现对象继承 function Parent(username) { this.username = username; this.sayHello = function() { alert(this.username); } } function Child(username, password) { Parent.apply(this, new Array(username)); this.password = password; this.sayWorld = function() { alert(this.password); } } var parent = new Parent("zhangsan"); var child = new Child("lisi", "123"); parent.sayHello(); child.sayHello(); child.sayWorld();
4）原型链方式（无法给构造函数传参数）
[html] view plaincopy print?
//使用原型链（prototype chain）方式实现对象继承 function Parent() { } Parent.prototype.hello = "hello"; Parent.prototype.sayHello = function() { alert(this.hello); } function Child() { } Child.prototype = new Parent(); Child.prototype.world = "world"; Child.prototype.sayWorld = function() { alert(this.world); } var child = new Child(); child.sayHello(); child.sayWorld();
5）混合方式（推荐）
[html] view plaincopy print?
//使用混合方式实现对象继承(推荐) function Parent(hello) { this.hello = hello; } Parent.prototype.sayHello = function() { alert(this.hello); } function Child(hello, world) { Parent.call(this, hello); this.world = world; } Child.prototype = new Parent(); Child.prototype.sayWorld = function() { alert(this.world); } var child = new Child("hello", "world"); child.sayHello(); child.sayWorld();
from: http://blog.csdn.net/csh624366188/article/details/7449000
总结
以上是生活随笔为你收集整理的Java程序员从笨鸟到菜鸟之（二十九）javascript对象的创建和继承实现的全部内容，希望文章能够帮你解决所遇到的问题。
如果觉得生活随笔网站内容还不错，欢迎将生活随笔推荐给好友。
