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：
String Trimming 字符串修剪
Removing leading and trailing whitespace from a string is a simple but common task. Although ECMAScript 5 adds a native string trim method (and you should therefore start to see this method in upcoming browsers), JavaScript has not historically in ......
Data Formats 数据格式
When considering data transmission techniques, you must take into account several factors: feature set, compatibility, performance, and direction (to or from the server). When considering data formats, the only scale you need for comparison is speed.
......
第八章 Programming Practices 编程实践
Every programming language has pain points and inefficient patterns that develop over time. The appearance of these traits occurs as people migrate to the language and start pushing its boundaries. Since 2005, when the term "Ajax" ......
JavaScript Minification JavaScript紧凑
JavaScript minification is the process by which a JavaScript file is stripped of everything that does not contribute to its execution. This includes comments and unnecessary whitespace. The process typically reduces the file size by ha ......
Summary 总结
When web pages or applications begin to feel slow, analyzing assets as they come over the wire and profiling scripts while they are running allows you to focus your optimization efforts where they are needed most.
当网页或应用程序变慢时，分� ......
