HTML5 programming with JavaScript for dummies

411 Pages·2013·19.68 MB·English

by  Mueller, John Paul

HTML5
Programming
with JavaScript
®
by John Paul Mueller
HTML5 Programming with JavaScript® For Dummies®
Published by
John Wiley & Sons, Inc.
111 River Street
Hoboken, NJ 07030-5774
www.wiley.com
Copyright © 2013 by John Wiley & Sons, Inc., Hoboken, New Jersey
Published simultaneously in Canada
No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or
by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permit-
ted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written
permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the
Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, [phone], fax [phone].
Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley
& Sons, Inc., 111 River Street, Hoboken, NJ 07030, [phone], fax [phone], or online at http://
www.wiley.com/go/permissions.
Trademarks: Wiley, the Wiley logo, For Dummies, the Dummies Man logo, A Reference for the Rest of Us!,
The Dummies Way, Dummies Daily, The Fun and Easy Way, Dummies.com, Making Everything Easier, and
related trade dress are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates
in the United States and other countries, and may not be used without written permission. JavaScript is
a registered trademark of Oracle America,Inc. All other trademarks are the property of their respective
owners. John Wiley & Sons, Inc. is not associated with any product or vendor mentioned in this book.
LIMIT OF LIABILITY/DISCLAIMER OF WARRANTY: THE PUBLISHER AND THE AUTHOR MAKE NO
REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS
OF THE CONTENTS OF THIS WORK AND SPECIFICALLY DISCLAIM ALL WARRANTIES, INCLUDING
WITHOUT LIMITATION WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE. NO WARRANTY
MAY BE CREATED OR EXTENDED BY SALES OR PROMOTIONAL MATERIALS. THE ADVICE AND
STRATEGIES CONTAINED HEREIN MAY NOT BE SUITABLE FOR EVERY SITUATION. THIS WORK IS
SOLD WITH THE UNDERSTANDING THAT THE PUBLISHER IS NOT ENGAGED IN RENDERING LEGAL,
ACCOUNTING, OR OTHER PROFESSIONAL SERVICES. IF PROFESSIONAL ASSISTANCE IS REQUIRED,
THE SERVICES OF A COMPETENT PROFESSIONAL PERSON SHOULD BE SOUGHT. NEITHER THE
PUBLISHER NOR THE AUTHOR SHALL BE LIABLE FOR DAMAGES ARISING HEREFROM. THE FACT
THAT AN ORGANIZATION OR WEBSITE IS REFERRED TO IN THIS WORK AS A CITATION AND/OR
A POTENTIAL SOURCE OF FURTHER INFORMATION DOES NOT MEAN THAT THE AUTHOR OR THE
PUBLISHER ENDORSES THE INFORMATION THE ORGANIZATION OR WEBSITE MAY PROVIDE OR
RECOMMENDATIONS IT MAY MAKE. FURTHER, READERS SHOULD BE AWARE THAT INTERNET
WEBSITES LISTED IN THIS WORK MAY HAVE CHANGED OR DISAPPEARED BETWEEN WHEN THIS
WORK WAS WRITTEN AND WHEN IT IS READ.
For general information on our other products and services, please contact our Customer Care
Department within the U.S. at 877-762-2974, outside the U.S. at 317-572-3993, or fax [phone].
For technical support, please visit www.wiley.com/techsupport.
Wiley publishes in a variety of print and electronic formats and by print-on-demand. Some material
included with standard print versions of this book may not be included in e-books or in print-on-demand.
If this book refers to media such as a CD or DVD that is not included in the version you purchased, you
may download this material at http://booksupport.wiley.com. For more information about Wiley
products, visit www.wiley.com.
Library of Congress Control Number: 2013936244
ISBN 978-1-118-43166-5 (pbk); ISBN 978-1-118-46209-6 (ebk);
ISBN 978-1-118-61188-3 (ebk); ISBN 978-1-118-49418-9 (ebk)
Manufactured in the United States of America
10 9 8 7 6 5 4 3 2 1
About the Author
John Mueller is a freelance author and technical editor. He has writing in his
blood, having produced 91 books and over 300 articles to date. The topics
range from networking to artificial intelligence and from database man-
agement to heads-down programming. Some of his current books include
Windows command-line references, books on VBA and Visio, several books
on C#, and an IronPython programmer’s guide. His technical editing skills
have helped more than 63 authors refine the content of their manuscripts.
John has provided technical editing services to both Data Based Advisor
and Coast Compute magazines. He’s also contributed articles to magazines
like such as Software Quality Connection, DevSource, InformIT, SQL Server
Professional, Visual C++ Developer, Hard Core Visual Basic, asp.netPRO,
Software Test and Performance, and Visual Basic Developer. Be sure to read
John’s blog at http://blog.johnmuellerbooks.com.
When John isn’t working at the computer, you can find him outside in the
garden, cutting wood, or generally enjoying nature. John also likes making
wine and knitting. When not occupied with anything else, he makes glycerin
soap and candles, which comes in handy for gift baskets. You can reach John
on the Internet at [email protected]. John is also setting up a
website at http://www.johnmuellerbooks.com. Feel free to take a look
and make suggestions on how he can improve it.

Dedication
Dedicated to people who have given me hope and who have helped me
realize new potential as an author; on the occasion of their 50th anniversary,
Bill and Karen Bridges.
Author’s Acknowledgments
Thanks to my wife, Rebecca, for working with me to get this book completed.
I really don’t know what I would have done without her help in researching
and compiling some of the information that appears in this book. She also did
a fine job of proofreading my rough draft. Rebecca keeps the house running
while I’m buried in work.
Russ Mullen deserves thanks for his technical edit of this book. He greatly
added to the accuracy and depth of the material you see here. Russ is always
providing me with great URLs for new products and ideas. However, it’s the
testing Russ does that helps most. He’s the sanity check for my work. Russ
also has different computer equipment than mine, so he’s able to point out
flaws that I might not otherwise notice.
Matt Wagner, my agent, deserves credit for helping me get the contract in
the first place and taking care of all the details that most authors don’t really
consider. I always appreciate his assistance. It’s good to know that someone
wants to help.
A number of people read all or part of this book to help me refine the
approach, test the coding examples, and generally provide input that all
readers wish they could have. These unpaid volunteers helped in ways too
numerous to mention here. I especially appreciate the efforts of Eva Beattie,
Glenn Russell, Osvaldo Téllez Almirall, and Gerald Wilson, Jr., who provided
general input, read the entire book, and selflessly devoted themselves to this
project.
Finally, I would like to thank Kim Darosett, Katie Feltman, Virginia Sanders,
Katie Crocker, and the rest of the editorial and production staff at Wiley for
their assistance in bringing this book to print. It’s always nice to work with
such a great group of professionals.
Publisher’s Acknowledgments
We’re proud of this book; please send us your comments at http://dummies.custhelp.com.
For other comments, please contact our Customer Care Department within the U.S. at 877-762-2974,
outside the U.S. at 317-572-3993, or fax [phone].
Some of the people who helped bring this book to market include the following:
Acquisitions and Editorial Composition Services
Senior Project Editor: Kim Darosett Project Coordinator: Katherine Crocker
Acquisitions Editor: Constance Santisteban Layout and Graphics: Amy Hassos,
Joyce Haughey
Copy Editor: Virginia Sanders
Proofreaders: Jessica Kramer, Lisa Stiers
Technical Editor: Russ Mullen
Indexer: Ty Koontz
Editorial Manager: Leah Michael
Editorial Assistant: Annie Sullivan
Senior Editorial Assistant: Cherie Case
Cover Photo: © kertlis/iStockphoto
Publishing and Editorial for Technology Dummies
Richard Swadley, Vice President and Executive Group Publisher
Andy Cummings, Vice President and Publisher
Mary Bednarek, Executive Acquisitions Director
Mary C. Corder, Editorial Director
Publishing for Consumer Dummies
Kathleen Nebenhaus, Vice President and Executive Publisher
Composition Services
Debbie Stailey, Director of Composition Services
Table of Contents
Introduction ................................................................. 1
About This Book ..............................................................................................1
What You Don’t Have to Read ........................................................................2
Foolish Assumptions .......................................................................................2
Conventions Used in This Book .....................................................................3
How This Book Is Organized ..........................................................................3
Part I: Understanding the Basics of JavaScript ..................................3
Part II: Speaking the JavaScript Language ..........................................4
Part III: Meeting JavaScript’s Control Structures ...............................4
Part IV: Interacting with Users and HTML ..........................................4
Part V: Extending JavaScript Further ..................................................5
Part VI: The Part of Tens .......................................................................5
The companion Website .......................................................................5
Icons Used in This Book .................................................................................6
Where to Go from Here ...................................................................................6
Part I: Understanding the Basics of JavaScript ............... 9
Chapter 1: HTML, Say Hello to JavaScript . . . . . . . . . . . . . . . . . . . . . . . . 11
Introducing JavaScript ..................................................................................12
Java and JavaScript aren’t long-lost relatives ..................................13
Recognizing the benefits of JavaScript .............................................13
Seeing How JavaScript Fits into an HTML Document ...............................16
Starting an HTML5 document ............................................................16
Understanding the alert() function ...................................................17
Using the <script> tag ..........................................................................18
Placing the code in the page heading................................................19
Relying on external files ......................................................................20
Chapter 2: Assessing Tools of the Trade . . . . . . . . . . . . . . . . . . . . . . . . . 23
Researching Browsers and Their Debugging Tools ..................................24
Catching up with Firefox .....................................................................25
Meeting Google Chrome ......................................................................29
Checking out native browsers: Internet Explorer or Safari ............33
Checking browser and version ..........................................................34
viii
HTML5 Programming with JavaScript For Dummies
Discovering Programs to Write JavaScript ................................................36
Using a text editor................................................................................37
Using a dedicated editor .....................................................................38
Hosting Your Site ...........................................................................................41
Quickly looking at Web hosting .........................................................41
Using JavaScript from your computer ..............................................42
Testing your installation .....................................................................46
Chapter 3: Integrating HTML5 and JavaScript . . . . . . . . . . . . . . . . . . . . 47
Creating Simple Output ................................................................................48
Writing to an HTML element ..............................................................48
Creating direct document output ......................................................50
Avoiding potential problems with output ........................................51
Working with JavaScript Statements ..........................................................52
Understanding the dot syntax ............................................................52
Adding multiple statements to a single script .................................53
Defining basic code blocks .................................................................55
Understanding case sensitivity ..........................................................55
Using white space effectively .............................................................55
Using the line continuation character ...............................................56
Writing Comments in JavaScript .................................................................57
Creating single-line comments ...........................................................58
Creating multi-line comments ............................................................59
Preventing code execution by using comments ..............................60
Alerting Visitors That JavaScript Has Something to Say ..........................60
Using the <noscript> tag .....................................................................60
Using styles ...........................................................................................61
Part II: Speaking the JavaScript Language ................... 63
Chapter 4: Embracing JavaScript Variables . . . . . . . . . . . . . . . . . . . . . . 65
Understanding Simple Variables .................................................................66
Seeing variables as storage bins ........................................................66
Declaring variables ..............................................................................67
Discovering variable types .................................................................68
Understanding undefined and null variables ...................................70
Working with Booleans .................................................................................71
Working with Numbers .................................................................................72
Understanding the operators .............................................................73
Doing simple math ...............................................................................78
Changing number formats ..................................................................80
Working with Text .........................................................................................83
Concatenating text ...............................................................................83
Changing word and letter formats .....................................................83