臭美 — Sat, 09 Oct 2010 02:28:00 GMT

1. 伪类(Pseudoclassical)
��单的��_��伪类��是通过定义一个构造函数�ƈ扩充它的prototype来实现的�?br />

<html>
<head>
<title>testtitle>
<script>
    function test(){
        var Father = function(firstName){
            this.firstName = firstName;
        };

        Father.prototype.name = function(){
            return this.firstName;
        };

        var Son = function(firstName, lastName){
            this.firstName = firstName;
            this.lastName = lastName;
        };

        Son.prototype = new Father();

        Son.prototype.name = function(){
            return this.firstName + " " + this.lastName;
        }

        var aSon = new Son("San", "Zhang");
        alert(aSon.name()); // San Zhang
    }
script>
<body onload="test()">
body>
head>
html>

可以看出�Q�这�U�方法是没有�U�有属性的�Q��ƈ且不能访问父�cȝ��Ҏ��?br />
2. 原型(Prototypal)
利用原型方式来实现��承，��摒弃了伪类中向“�c?#8221;�q�种方式靠拢的方法，而是用纯�_�的对象来实现�?br />

<html>
<head>
<title>testtitle>
<script>
    function test(){
        var aFather = {
            firstName: "San",
            lastName: "Zhang",
            getName: function(){
                return this.firstName + " " + this.lastName;
            }
        };

        var Son = function(){};
        Son.prototype = aFather;

        var aSon = new Son();
        aSon.firstName = "XiaoSan";
        alert(aSon.getName()); // XiaoSan Zhang
        alert(Son.prototype.getName()); // San Zhang
    }
script>
<body onload="test()">
body>
head>
html>

可以看出�Q�现在的�l�承是纯�_�的对象与对象间的了�Q�不�q�还有个问题�Q�这个方式依然没有解军_��性隐藏�?br />
3. 函数�?Functional)
使用函数化方法可以通过闭包有效的实��C��息隐藏，不过看�v来就没有原型方式直观了�?/p>

<html>
<head>
<title>testtitle>
<script>
    function test(){
        var father = function(firstName, lastName){
            var instance = {};

            // 对外暴露的方法，此时firstName和lastName�{�于被隐藏了
            instance.getFirstName = function(){
                return firstName;
            };

            instance.getLastName = function(){
                return lastName;
            };

            instance.getName = function(){
                return firstName + " " + lastName;
            };

            return instance;
        };

        var son = function(firstName, lastName){
            // �q�里��像OO语言一��P��先调用父�cȝ��构造函�?/span>
            var instance = father(firstName, lastName);

            // 扩充�Ҏ��Q�这里可以直接��?#8220;父类”的方法，不过属性已�l�变化了
            instance.nickname = function(){
                return "Little " + instance.getLastName();
            };

            return instance;
        }

        var aFather = father("San", "Zhang");
        var aSon = son("XiaoSan", "Zhang");
        alert(aFather.getName()); // San Zhang
        alert(aSon.getName()); // XiaoSan Zhang
        alert(aSon.nickname()); // Litttle Zhang
    }
script>
<body onload="test()">
body>
head>
html>

臭美 2010-10-09 10:28 发表评论

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