Book Image

Learning jQuery 1.3

By : Jonathan Chaffer, Karl Swedberg
Book Image

Learning jQuery 1.3

By: Jonathan Chaffer, Karl Swedberg

Overview of this book

<p>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. <br /><br />Revised and updated for version 1.3 of jQuery, this book teaches you 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.<br /><br />In this book, the authors share their knowledge, experience, and enthusiasm about jQuery to help you get the most from the library and to make your web applications shine. The book introduces jQuery and shows how you can write a functioning jQuery program in just three lines of code. It then guides you through CSS selectors and shows how to enhance the basic event handling mechanisms to give them a more elegant syntax. You will then learn to add impact to your actions through a set of simple visual effects and also to create, copy, reassemble, and embellish content using jQuery's DOM modification methods. You will also learn to send and retrieve information with AJAX methods. The book will then step you through many detailed, real-world examples and even equip you to extend the jQuery library itself with your own plug-ins.</p>
Table of Contents (22 chapters)
Learning jQuery 1.3
Credits
Foreword
About the Authors
About the Reviewers
Preface
Index

Adding jQuery Object Methods


Most of jQuery's built-in functionality is provided through its object 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 object 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.');
}

Note

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:

$('div').myMethod();

Our alert is displayed 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 plugin method, the keyword this is set to the current...