Aprendiendo Jquery

Learning jQuery
Third Edition

Create better interaction, design, and web development
with simple JavaScript techniques

Jonathan Chaffer
Karl Swedberg

BIRMINGHAM - MUMBAI

Learning jQuery
Third Edition
Copyright © 2011 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval
system, or transmitted in any form or by any means, withoutthe prior written
permission of the publisher, except in the case of brief quotations embedded in
critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy
of the information presented. However, the information contained in this book is
sold without warranty, either express or implied. Neither the authors, nor Packt
Publishing, and itsdealers and distributors will be held liable for any damages
caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the
companies and products mentioned in this book by the appropriate use of capitals.
However, Packt Publishing cannot guarantee the accuracy of this information.

First published:September 2011

Production Reference: 1160911

Published by Packt Publishing Ltd.
Livery Place
35 Livery Street
Birmingham B3 2PB, UK..
ISBN 978-1-84951-654-9
www.packtpub.com

Cover Image by Karl Swedberg (kswedberg@gmail.com)

Credits
Authors
Jonathan Chaffer

Proofreader
Linda Morris

Karl Swedberg
Indexers
Reviewers
Kaiser Ahmed

Tejal Daruwale
Rekha Nair

Kevin BoudlocheCarlos Estebes
Acquisition Editor
Sarah Cullington
Development Editor

Graphics
Nilesh Mohite
Production Coordinators
Aparna Bhagat
Prachali Bhiwandkar

Roger D'souza
Cover Work
Technical Editors
Llewellyn F. Rozario
Azharuddin Sheikh
Project Coordinator
Srimoyee Ghoshal

Aparna Bhagat
Prachali Bhiwandkar

Foreword
I feel honored knowing that Karl Swedberg and JonathanChaffer undertook the task
of writing Learning jQuery. As the first book about jQuery, it set the standard that
other jQuery—and, really, other JavaScript books in general—have tried to match.
It's consistently been one of the top selling JavaScript books since its release, in no
small part due to its quality and attention to detail.
I'm especially pleased that it was Karl and Jonathan whowrote the book as I already
knew them so well and knew that they would be perfect for the job. Being part of
the core jQuery team, I've had the opportunity to come to know Karl quite well over
the past couple years, and especially within the context of his book writing effort.
Looking at the end result, it's clear that his skills as both a developer and a former
English teacher were perfectlydesigned for this singular task.
I've also had the opportunity to meet both of them in person, a rare occurrence in
the world of distributed Open Source projects, and they continue to be upstanding
members of the jQuery community.
The jQuery library is used by so many different people in the jQuery community.
The community is full of designers, developers, people who have experienceprogramming, and those who don't. Even within the jQuery team, we have people
from all backgrounds providing their feedback on the direction of the project. There
is one thing that is common across all of jQuery's users, though: We are a community
of developers and designers who want JavaScript development to be made simple.
It's almost a cliché, at this point, to say that an open source project iscommunityoriented, or that a project wants to focus on helping new users get started. However,
it's not just an empty gesture for jQuery; it's the liquid-oxygen fuel for the project.
We actually have more people in the jQuery team dedicated to managing the jQuery
community, writing documentation, or writing plugins than actually maintaining
the core code base. While the health of the library is...