Book Image

Learning jQuery - Fourth Edition - Fourth Edition

Book Image

Learning jQuery - Fourth Edition - Fourth Edition

Overview of this book

To build interesting, interactive sites, developers are turning to JavaScript libraries such as jQuery to automate common tasks and simplify complicated ones. Because many web developers have more experience with HTML and CSS than with JavaScript, the library's design lends itself to a quick start for designers with little programming experience. Experienced programmers will also be aided by its conceptual consistency. LearningjQuery - Fourth Edition is revised and updated version of jQuery. You will learn the basics of jQuery for adding interactions and animations to your pages. Even if previous attempts at writing JavaScript have left you baffled, this book will guide you past the pitfalls associated with AJAX, events, effects, and advanced JavaScript language features. Starting with an introduction to jQuery, you will first be shown how to write a functioning jQuery program in just three lines of code. Learn how to add impact to your actions through a set of simple visual effects and to create, copy, reassemble, and embellish content using jQuery's DOM modification methods. The book will take you through many detailed, real-world examples, and even equip you to extend the jQuery library itself with your own plug-ins.
Table of Contents (24 chapters)
Learning jQuery Fourth Edition
About the Authors
About the Reviewers

Adding jQuery object methods

Most of jQuery's built-in functionality is provided through its object instance methods, and this is where plugins shine as well. Whenever we would write a function that acts on part of the DOM, it is probably appropriate instead to create an instance method.

We have seen that adding global functions requires extending the jQuery object with new methods. Adding instance methods is similar, but we instead extend the jQuery.fn object:

jQuery.fn.myMethod = function() {
  alert('Nothing happens.');


The jQuery.fn object is an alias to jQuery.prototype, provided for conciseness.

We can then call this new method from our code after using any selector expression:


Our alert is displayed (once for each <div> in the document) when we invoke the method. We might as well have written a global function, though, as we haven't used the matched DOM nodes in any way. A reasonable method implementation acts on its context.

Object method context

Within any...