Example of the use of jquery $.fn

$.fn refers to the jquery namespace, plus the methods and properties on the FN, which are valid for each jquery instance.

If the extension $.fn.abc (), or $.FN.ABC () is a method of extending an ABC to jquery, then each jquery instance can invoke the method.

For example: $ ("#div"). ABC ();

jquery provides two methods for development, namely:

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

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

Example:

$.extend ({    add:function (b) {return a +b;}}) Can be understood as a static method, the actual invocation of $.add (3,4); // 7

$. ("#btn1") generates an instance of the jquery class.

Jquery.fn.extend (object); To extend the jquery.prototype is to add "member functions" to the jquery class, and the jquery instance can use "member functions".

For example to develop a plugin, make a special edit box when he is clicked, then alert the current edit box contents

$.fn.extend ({alertwwhileclick:function () {$ (this). Click (function () {  alert ($ (  this). Val ()); })})

Example of the use of jquery $.fn