Extend and Fn.extend of jquery

jquery has two methods for developing plug-ins, namely:

JQuery.fn.extend (object);

Jquery.extend (object);

Jquery.extend (object); To extend the jquery class itself. Adds a new method to the class.

JQuery.fn.extend (object); Adds a method to a jquery object.

What's the FN thing? If you look at the jquery code, it's not hard to find.

Jquery.fn = Jquery.prototype = {

Init:function (Selector, context) {//....

//......

};

The original Jquery.fn = Jquery.prototype. It's certainly not strange to prototype.

Although JavaScript does not have a clear class concept, it is more convenient to use a class to understand it.

jquery is a well-encapsulated class, such as we use the statement $ ("#btn1") to generate an instance of the jquery class.

Jquery.extend (object); Adding a class method to the jquery class can be understood as adding a static method. Such as:

$.extend ({

Add:function (A, b) {return a+b;}

});

Adds a "static method" for jquery to add, which can then be used where jquery is introduced,

$.add (3,4); Return 7

JQuery.fn.extend (object); The extension to Jquery.prototype is to add "member functions" to the jquery class. An instance of the jquery class can use this "member function".

For example, we want to develop a plugin, make a special edit box, when it is clicked, then alert the contents of the current edit box. You can do this:

1. $.fn.extend ({    
2.     
3.     alertwhileclick:function () {    
4.    
5.         $ (this). Click (function () {    
6.    
7.              alert ($ (this). Val ());     
8.          });     
9.     
10.      }    
11.     
12. });     
13.     
14. $ (//page: <input id= "input1"  type= "text"/>&NBSP;&NBSP;&NBSP;

$ ("#input1") is a jquery instance, and when it calls the Member method Alertwhileclick, it implements the extension, which pops up the contents of the current edit each time it is clicked.

The real development process, of course, do not make such a small white plug-in, in fact, jquery arch a wealth of operating documents, events, CSS, Ajax, effects of methods, combined with these methods, you can develop more niubility plug-ins.

(turn) Source: http://www.cnblogs.com/yuanyuan/

Extend and Fn.extend of jquery