Professional Ajax

611 Pages·2007·4.66 MB·English

by  Nicholas C Zakas

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Professional
Ajax
2nd Edition
Nicholas C. Zakas
Jeremy McPeak
Joe Fawcett
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Professional Ajax, 2nd Edition
Published by
Wiley Publishing, Inc.
10475 Crosspoint Boulevard
Indianapolis, IN 46256
www.wiley.com
Copyright © 2007 by Wiley Publishing, Inc., Indianapolis, Indiana
Published simultaneously in Canada
ISBN: 978-0-470-10949-6
Manufactured in the United States of America
10 9 8 7 6 5 4 3 2 1
Library of Congress Cataloging-in-Publication Data:˙
Zakas, Nicholas C.
Professional Ajax / Nicholas C. Zakas, Jeremy McPeak, Joe Fawcett. -- 2nd ed.
p. cm.
Includes index.
ISBN-13: 978-0-470-10949-6 (paper/website)
ISBN-10: 0-470-10949-1 (paper/website)
1. Ajax (Web site development technology) 2. Web sites--Design--Computer programs. 3. JavaScript (Computer pro-
gram language) 4. Asynchronous transfer mode. 5. World Wide Web. I. McPeak, Jeremy, 1979- II. Fawcett, Joe, 1962-
III. Title.
TK5105.8885.A52Z35 2007
005.13'3--dc22
2006103094
No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any
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To mom, dad, Greg, Yiayia, and the rest of my family and friends who have
supported me throughout my cross-country move.
—Nicholas C. Zakas
To the love of my life, Starla. Thank you for your love, patience, and
encouragement.
—Jeremy McPeak
To my parents, Sheila and William, who instilled in me a love of reading.
Thank you!
—Joe Fawcett
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About the Authors
Nicholas C. Zakashas a BS in Computer Science from Merrimack College and an MBAfrom Endicott
College. He is the author of Professional JavaScript for Web Developers(Wiley 2005) as well as several
online articles. Nicholas works for Yahoo! as a frontend engineer and has worked in web development
for more than 6 years, during which time he has helped develop web solutions in use at some of the
largest companies in the world. Nicholas can be reached through his web site at www.nczonline.net.
Jeremy McPeakbegan tinkering with web development as a hobby in 1998. Currently working in the IT
department of a school district, Jeremy has experience developing web solutions with JavaScript, PHP,
and C#. He has written several online articles covering topics such as XSLT, WebForms, and C#. He is
also co-author of Beginning JavaScript, 3rd Edition(Wiley 2007). Jeremy can be reached through his web
site at www.wdonline.com.
Joe Fawcett started programming in the 1970s and briefly worked in IT upon leaving full-time educa-
tion. He then pursued a more checkered career before returning to software development in 1994. In
2003 he was awarded the title of Microsoft Most Valuable Professional in XMLfor community contribu-
tions and technical expertise. He currently works in London as a developer for FTC Kaplan, a leading
international provider of accountancy and business training, where he specializes in systems integration.
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Credits
Senior Acquisitions Editor Vice President and Executive Publisher
Jim Minatel Joseph B. Wikert
Senior Development Editor Graphics and Production Specialists
Kevin Kent Sean Decker
Jennifer Mayberry
Technical Editor Amanda Spagnuolo
Alexei Gorkov Alicia B. South
Production Editor Quality Control Technician
Angela Smith RobSpringer
Copy Editor Project Coordinator
Jeri Freedman Bill Ramsey
Editorial Manager Proofreading
Mary Beth Wakefield Christopher Jones
Production Manager Indexing
Tim Tate Johnna VanHoose Dinse
Vice President and Executive Group Publisher Anniversary Logo Design
Richard Swadley Richard Pacifico
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Acknowledgments
It takes many people to create a book such as this, and as such, we’d like to thank some people for their
contributions to this work.
First and foremost, thanks to everyone at Wiley for their support: to Jim Minatel for starting the process
once again, and Kevin Kent for putting up with all of the last-minute changes and course diversions
throughout the process. Also, a thanks to our technical editor, Alexei Gorkov, for doing a fantastic job
keeping us honest.
Last, a big thanks to those who provided feedback pre-publication including Peter Frueh, Adam Moore,
Jenny Han, Matt Sweeney, Tyson Guskiken, Steve Carlson, and especially Hedger Wang, who suggested
adding the chapter on request management.
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Contents
Introduction xv
Chapter 1: What Is Ajax? 1
Ajax Is Born 2
The Evolution of the Web 2
JavaScript 2
Frames 3
The Hidden Frame Technique 3
Dynamic HTML and the DOM 3
Iframes 4
XMLHttp 4
The Real Ajax 5
Ajax Principles 6
Technologies behind Ajax 6
Who Is Using Ajax? 7
Google Suggest 7
Gmail 8
Google Maps 9
A9 10
Yahoo! News 11
Bitflux Blog 12
Confusion and Controversy 13
Ajax and Web 2.0 14
Summary 15
Chapter 2: Ajax Basics 17
HTTP Primer 17
HTTP Requests 18
HTTP Responses 20
Ajax Communication Techniques 21
The Hidden Frame Technique 21
XMLHttp Requests (XHR) 37
Ajax with Images 50
Dynamic Script Loading 59
Cache Control 63
Summary 63
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Contents
Chapter 3: Ajax Patterns 65
Communication Control Patterns 65
Predictive Fetch 66
Page Preloading Example 66
Submission Throttling 74
Incremental Form Validation Example 76
Incremental Field Validation Example 82
Periodic Refresh 85
New Comment Notifier Example 86
Multi-Stage Download 90
Additional Information Links Example 91
Fallback Patterns 93
Cancel Pending Requests 94
Try Again 96
Summary 97
Chapter 4: Ajax Libraries 99
The Yahoo! Connection Manager 99
Setup 99
Basic Requests 100
The Callback Object 100
Monitoring and Managing Requests 104
Form Interaction 104
File Uploads 105
GET Example 106
POST Example 107
Additional Features 108
Limitations 108
Prototype 109
The Ajax.Request Object 109
The Options Object 109
GET Example 112
POST Example 113
The Ajax.Updater Object 113
The Ajax.Responders Object 115
Advantages and Disadvantages 117
jQuery 117
Simple jQuery Expressions 117
Executing GET Requests 118
GET Example 119
viii
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Contents
The $.post() Method 120
POST Example 120
The load() Method 122
The $.ajax() Method 123
The ajaxStart() and ajaxStop() Methods 124
Limitations 124
Summary 125
Chapter 5: Request Management 127
Priority Queues 127
The RequestManager Object 131
Request Description Objects 132
Queuing Requests 133
Sending Requests 134
Cancelling Requests 139
Age-Based Promotion 141
Handling Ajax Patterns 142
Using RequestManager 145
Summary 148
Chapter 6: XML, XPath, and XSLT 149
XML Support in Browsers 149
XML DOM in IE 149
XML in Other Browsers 159
Cross-Browser XML 162
A Basic XML Example 163
XPath Support in Browsers 170
Introduction to XPath 170
XPath in IE 172
Working with Namespaces 173
XPath in Other Browsers 175
Working with a Namespace Resolver 177
Cross-Browser XPath 178
XSL Transformation Support in Browsers 179
Introduction to XSLT 180
XSLT in IE 182
XSLT in Other Browsers 187
Cross-Browser XSLT 189
Best Picks Revisited 189
Summary 192
ix
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Contents
Chapter 7: Syndication with RSS and Atom 193
RSS 193
RSS 0.91 194
RSS 1.0 195
RSS 2.0 196
Atom 196
XParser 197
The xparser Namespace 197
Retrieving the Data 198
The Abstract Classes 198
Creating a News Ticker 210
The Server-Side Component 210
The Client-Side Component 211
Styling the News 221
Using the News Ticker Widget 222
Web Search with RSS 223
The Server-Side Component 224
The Client-Side Component 225
Customizing the Web Search Widget 232
Using the Web Search Widget 234
Summary 235
Chapter 8: JSON 237
What Is JSON? 237
Array Literals 237
Object Literals 238
Mixing Literals 239
JSON Syntax 240
JSON Encoding/Decoding 241
JSON versus XML 242
Server-Side JSON Tools 243
JSON-PHP 243
Other Tools 245
Creating an Autosuggest Textbox 246
Functionality Overview 246
The HTML 247
The Database Table 249
The Architecture 249
The Classes 250
The AutoSuggest Control 250
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