JavaScript中的私有属性

一、使用构造函数获得私有属性：

 function Gadget(){
     var name = 'iPod';
     this.getName = function(){
         return name;
     };
 };

 var toy = new Gadget();
 console.log(toy.name);//undefined
 console.log(toy.getName());//iPod

注意，当返回变量为数组或对象时，私有性失效：

function Gadget(){
    var specs = {
        width: 400,
        height: 500
    };
    this.getSpecs = function(){
        return specs;
    };
};

var toy = new Gadget();
var specs = toy.getSpecs();
specs.color = 'black';
console.log(toy.getSpecs());//{ width: 400, height: 500, color: 'black' }

二、使用对象字面量

 var myobj = (function(){
     var name = 'wqh';
     return {
         getName: function(){
             return name;
         }
     }
 })();
 console.log(myobj.name);//undefined
 console.log(myobj.getName());//wqh

三、共享的私有属性：prototype中

 function Gadget(){
     var name = 'iPod';
     this.getName = function(){
         return name;
     };
 };

 Gadget.prototype = (function(){
     var browser = 'Webkit';
     return {
         getBrowser: function(){
             return browser;
         }
     };
 })();

 var toy = new Gadget();

 console.log(toy.name);//undefined
 console.log(toy.getName());//iPod
 console.log(toy.browser);//undefined
 console.log(toy.getBrowser());//Webkit

注：JavaScript模式P94-98