$.fn refers to the jquery namespace, plus the methods and properties on FN, which are valid for each of the jquery instances.
If the extension $.fn.abc (), that is, $.FN.ABC () is an ABC method extended to jquery, then each of your jquery instances can be referenced in the following way.
Then you can look like this: $ ("#div"). ABC ();
jquery has two methods for developing Plug-ins, respectively:
Jquery.extend (object); To extend the jquery class itself. Adds a new method to the class.
JQuery.fn.extend (object); Add methods to the JQuery object.
What is FN? See the jquery code, it's not hard to find.
Copy Code code as follows:
Jquery.fn = Jquery.prototype ={
Init:function (Selector, context) {//....
//......
};
Originally JQUERY.FN =jquery.prototype. To prototype certainly not strange.
jquery is a very nicely encapsulated class, for example, we use statement $ ("#btn1") to generate an instance of a jquery class.
Jquery.extend (object); Adding a class method to the jquery class can be understood as adding a static method. Such as:
Copy Code code as follows:
$.extend ({
Add:function (a,b) {returna+b;}
});
Add a "static method" for jquery, and then you can use this method in the place where jquery is introduced,
$.add (3,4); Return 7
JQuery.fn.extend (object), and extending to Jquery.prototype, is to add a "member function" for the jquery class. Examples of jquery classes can use this "member function".
For example, we want to develop a plugin, make a special edit box, when it is clicked, alert the contents of the current edit box. Can do this:
jquery Code
Copy Code code as follows:
$.fn.extend ({
Alertwhileclick:function () {
$ (this). Clic K (function () {
Alert ($ (this). Val ());
});
}
});
