javascript prototype介绍的文章
JavaScript是基于对象的，任何元素都可以看成对象。然而，类型和对象是不同的。本文中，我们除了讨论类型和对象的一些特点之外，更重要的是研究如何写出好的并且利于重用的类型。毕竟，JavaScript这种流行的脚本语言如果能够进行良好的封装，并形成一个庞大的类型库，对于重用是非常有意义的。
网上对于prototype的文章很多，一直没明白核心的思想。最后写了很多例子代码后才明白：prototype只能用在类型上。
以下是一些关于类型和对象的例子，大家看完例子后可能更容易理解类型和对象之间的联系：
例子代码 说明
1 Object.prototype.Property = 1;
Object.prototype.Method = function ()
{
alert(1);
}
var obj = new Object();
alert(obj.Property);
obj.Method();
可以在类型上使用proptotype来为类型添加行为。这些行为只能在类型的实例上体现。
JS中允许的类型有Array, Boolean, Date, Enumerator, Error, Function, Number, Object, RegExp, String
2 var obj = new Object();
obj.prototype.Property = 1; //Error
//Error
obj.prototype.Method = function()
{
alert(1);
}
在实例上不能使用prototype，否则发生编译错误
3 Object.Property = 1;
Object.Method = function()
{
alert(1);
}
alert(Object.Property);
Object.Method();
可以为类型定义“静态”的属性和方法，直接在类型上调用即可
4 Object.Property = 1;
Object.Method = function()
{
alert(1);
}
var obj = new Object();
alert(obj.Property); //Error
obj.Method(); //Error
实例不能调用类型的静态属性或方法，否则发生对象未定义的错误。
5 function Aclass()
{
this.Property = 1;
this.Method = function()
{
alert(1);
}
}
var obj = new Aclass();
alert(obj.Property);
obj.Method();
这个例子演示了通常的在JavaScript中定义一个类型的方法
6 function Aclass()
{
this.Property = 1;
this.Method = function()
{
alert(1);
}
}
Aclass.prototype.Property2 = 2;
Aclass.prototype.Method2 = function
{
alert(2);
}
var obj = new Aclass();
alert(obj.Property2);
obj.Method2();
可以在�
相关文档：
Regular Expression Optimization 正则表达式优化
Incautiously crafted regexes can be a major performance bottleneck (the upcoming section, "Runaway Backtracking" on page 91, contains several examples showing how severe this can be), but there is a lot you can do to improve re ......
Yielding with Timers 用定时器让出时间片
Despite your best efforts, there will be times when a JavaScript task cannot be completed in 100 milliseconds or less because of its complexity. In these cases, it's ideal to yield control of the UI thread so that UI updates may occur ......
Use the Fast Parts 使用速度快的部分
Even though JavaScript is often blamed for being slow, there are parts of the language that are incredibly fast. This should come as no surprise, since JavaScript engines are built in lower-level languages and are therefore compiled. Thou ......
第十章 Tools 工具
Having the right software is essential for identifying bottlenecks in both the loading and running of scripts. A number of browser vendors and large-scale websites have shared techniques and tools to help make the Web faster and more efficient. This ......
