Sams Teach Yourself AJAX in 10 Minutes

241 Pages·2006·4.05 MB·English

by  Phil Ballard

Teach
Yourself
A jax
10
in
Minutes
Phil Ballard
800 East 96th Street,Indianapolis,Indiana,46240 USA
Sams Teach Yourself ACQUISITIONSEDITOR
Linda Harrison
Ajax in 10 Minutes
DEVELOPMENTEDITOR
Copyright  2006 by Sams Publishing Damon Jordan
All rights reserved. No part of this book shall be reproduced,
MANAGINGEDITOR
stored in a retrieval system,or transmitted by any means,elec-
Charlotte Clapp
tronic,mechanical,photocopying,recording,or otherwise,without
written permission from the publisher. No patent liability is
PROJECTEDITOR
assumed with respect to the use of the information contained
Seth Kerney
herein. Although every precaution has been taken in the prepara-
tion of this book,the publisher and author assume no responsibility COPYEDITOR
for errors or omissions. Nor is any liability assumed for damages
Geneil Breeze
resulting from the use of the information contained herein.
International Standard Book Number:0-672-32868-2 INDEXER
Ken Johnson
Library of Congress Catalog Card Number:2005934928
Printed in the United States of America PROOFREADER
First Printing:April 2006 Leslie Joseph
09 08 07 06 4 3 2 1
TECHNICALEDITOR
Trademarks Bill Bercik
All terms mentioned in this book that are known to be trade- PUBLISHING
marks or service marks have been appropriately capitalized. COORDINATOR
Sams Publishing cannot attest to the accuracy of this informa- Vanessa Evans
tion. Use of a term in this book should not be regarded as
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DEVELOPER
Warning and Disclaimer Dan Scherf
Every effort has been made to make this book as complete and INTERIORDESIGNER
as accurate as possible,but no warranty or fitness is implied. Gary Adair
The information provided is on an “as is”basis. The author and
the publisher shall have neither liability nor responsibility to COVERDESIGNER
any person or entity with respect to any loss or damages arising Aren Howell
from the information contained in this book or from the use of
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Contents
Introduction 1
About This Book..................................................................................1
What Is Ajax?......................................................................................1
Who This Book Is For ........................................................................3
What Do I Need To Use This Book?..................................................3
Conventions Used in This Book..........................................................3
Online Resources and Errata ..............................................................4
PART I A Refresher on Web Technologies
1 Anatomy of a Website 5
A Short History of the Web ................................................................5
Workings of the World Wide Web ......................................................6
Summary............................................................................................12
2 Writing Web Pages in HTML 13
Introducing HTML............................................................................13
Elements of an HTML Page..............................................................16
A More Advanced HTML Page........................................................21
Some Useful HTML Tags..................................................................23
Cascading Style Sheets in Two Minutes............................................25
Summary............................................................................................26
3 Sending Requests Using HTTP 27
Introducing HTTP..............................................................................27
The HTTP Request and Response ....................................................28
HTML Forms ....................................................................................31
Summary............................................................................................35
iv Sams Teach Yourself Ajax in Ten Minutes
4 Client-Side Coding Using JavaScript 36
About JavaScript................................................................................36
In at the Deep End ............................................................................38
Manipulating Data in JavaScript........................................................49
Summary............................................................................................52
5 Server-Side Programming in PHP 53
Introducing PHP................................................................................53
Embedding PHP in HTML Pages......................................................54
Variables in PHP................................................................................56
Controlling Program Flow ................................................................58
Summary............................................................................................60
6 A Brief Introduction to XML 61
Introducing XML ..............................................................................61
XML Basics ......................................................................................62
JavaScript and XML..........................................................................66
The Document Object Model (DOM) ..............................................67
Summary............................................................................................69
PART II Introducing Ajax
7 Anatomy of an Ajax Application 70
The Need for Ajax ............................................................................70
Introducing Ajax................................................................................73
The Constituent Parts of Ajax............................................................75
Putting It All Together ......................................................................78
Summary............................................................................................79
8 The XMLHTTPRequest Object 80
More About JavaScript Objects ........................................................80
IntroducingXMLHTTPRequest..............................................................82
Creating the XMLHTTPRequestObject................................................83
Summary............................................................................................90
Contents v
9 Talking with the Server 91
Sending the Server Request ..............................................................91
Monitoring Server Status ..................................................................97
The Callback Function......................................................................99
Summary..........................................................................................101
10 Using the Returned Data 102
TheresponseTextandresponseXMLProperties..............................102
Another Useful JavaScript DOM Property......................................107
Parsing responseXML........................................................................108
Providing User Feedback................................................................109
Summary..........................................................................................111
11 Our First Ajax Application 112
Constructing the Ajax Application..................................................112
The HTML Document ....................................................................112
Adding JavaScript............................................................................114
Putting It All Together ....................................................................118
Summary..........................................................................................122
PART III More Complex Ajax
Technologies
12 Returning Data as Text 123
Getting More from the responseTextProperty..............................123
Summary..........................................................................................130
13 AHAH—Asynchronous HTML and HTTP 131
Introducing AHAH..........................................................................131
Creating a Small Library for AHAH ..............................................132
Using myAHAHlib.js......................................................................135
Summary..........................................................................................141
vi Sams Teach Yourself Ajax in Ten Minutes
14 Returning Data as XML 142
Adding the “x”to Ajax....................................................................142
TheresponseXMLProperty..............................................................143
Project—An RSS Headline Reader ................................................148
Summary..........................................................................................156
15 Web Services and the REST Protocol 157
Introduction to Web Services..........................................................157
REST—Representational State Transfer ........................................158
Using REST in Practice ..................................................................160
REST and Ajax................................................................................165
Summary..........................................................................................165
16 Web Services Using SOAP 166
Introducing SOAP (Simple Object Access Protocol)......................166
The SOAP Protocol ........................................................................167
Using Ajax and SOAP ....................................................................170
Reviewing SOAP and REST ..........................................................172
Summary..........................................................................................172
17 A JavaScript Library for Ajax 173
An Ajax Library ..............................................................................173
Reviewing myAHAHlib.js ..............................................................174
Implementing Our Library..............................................................175
Using the Library ............................................................................179
Extending the Library......................................................................182
Summary..........................................................................................183
18 Ajax “Gotchas” 184
Common Ajax Errors ......................................................................184
The Back Button..............................................................................184
Bookmarking and Links..................................................................185
Telling the User That Something Is Happening..............................186
Making Ajax Degrade Elegantly ....................................................186
Dealing with Search Engine Spiders ..............................................187
Pointing Out Active Page Elements................................................188
Don’t Use Ajax Where It’s Inappropriate........................................189
Security............................................................................................189
Contents vii
Test Code Across Multiple Platforms..............................................189
Ajax Won’t Cure a Bad Design ......................................................190
Some Programming Gotchas ..........................................................190
Summary..........................................................................................192
PART IV Commercial and Open Source
Ajax Resources
19 The prototype.js Toolkit 193
Introducing prototype.js..................................................................193
WrappingXMLHTTPRequest—theAjaxObject ................................196
Example Project—Stock Price Reader............................................199
Summary..........................................................................................202
20 Using Rico 203
Introducing Rico..............................................................................203
Rico’s Other Interface Tools............................................................208
Summary..........................................................................................214
21 Using XOAD 215
Introducing XOAD..........................................................................215
XOAD HTML..................................................................................219
Advanced Programming with XOAD..............................................222
Summary..........................................................................................223
Index 224
About the Author
Phil Ballard graduated in 1980 with an honors degree in electronics from
the University of Leeds,England. Following an early career as a research
scientist with a major multinational,Phil spent a few years in commercial
and managerial roles within the high technology sector,later working full
time as a software engineering consultant.
Operating as “The Mouse Whisperer”(http://www.mousewhisperer.
co.uk),Phil has spent recent years involved solely in website and intranet
design and development for an international portfolio of clients. Another
of his websites,http://www.crackajax.net,is home to an active and fast-
growing Ajax programming community.
Phil is currently based in southeast England. In his spare time,he still
plays bass guitar in rock bands,despite being easily old enough to know
better.
Dedication
To Sue,for her endless patience and support during the writing of this
book—and at all other times,too.
Acknowledgments
I would like to offer my sincere thanks for the team at Sams Publishing,
especially Linda Harrison,Shelley Johnston,Damon Jordan,Seth Kerney,
Geneil Breeze,and Andrea Bledsoe.
Bill Bercik deserves special thanks,not only for his excellent work as
technical editor,but also for his article at http://www.webpasties.com that
inspired my interest in Ajax in the first place.
I would also like to express my gratitude to the countless individuals who
have shared their knowledge and skill by writing open source software,
Internet articles,and tutorials. Without their contributions,this book,and
a great deal else,would not have been possible.