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

DOM traversal methods


The jQuery selectors that we have explored so far allow us to select a set of elements as we navigate across and down the DOM tree and filter the results. If this were the only way to select elements, our options would be quite limited (although, frankly, the selector expressions are robust in their own right, especially when compared to the regular DOM scripting options). There are many occasions when selecting a parent or ancestor element is essential; that is where jQuery's DOM traversal methods come into play. With these methods at our disposal, we can go up, down, and all around the DOM tree with ease.

Some of the methods have a nearly identical counterpart among the selector expressions. For example, the line we first used to add the alt class, $('tr:odd').addClass('alt');, could be rewritten with the .filter() method as follows:

$('tr').filter(':odd').addClass('alt');

For the most part, however, the two ways of selecting elements complement each other. Also, the...