Java Script For Dummies

Introduction

Welcome to the wonderful world of Web programming with JavaScript.

If you’ve worked with HTML before but want to add more flexibility

and punch to your pages, or even if you’ve never written a stick of code in

your life but are eager to hop on the Infobahn-wagon, this book’s for you.

Although I don’t assume that you know HTML, much of what you want to

do with JavaScript is interact with objects created by using HTML — so you

understand the examples in this book that much quicker if you have a good

HTML reference handy. One to consider is HTML 4 For Dummies, 4th Edition,

by Ed Tittel (Wiley Publishing, Inc.).

I do my best to describe how JavaScript works by using real-world examples —

and not a foo (bar) in sight. When explaining things in formal notation makes

sense, I do that, but not without a recap in plain English. Most importantly, I

include tons of sample programs that illustrate the kinds of things you may

want to do in your own pages.

Along with this book comes a companion CD-ROM. This CD-ROM contains all

the sample code listings covered in the text along with many other interesting

scripts, examples, and development tools. From experience, I can tell you that

the best way to get familiar with JavaScript is to load the scripts and interact

with them as you read through each chapter. If it’s feasible for you, I suggest

installing the contents of the CD right away, before you dig into the chapters.

Then, when you come across a listing in the book, all you have to do is doubleclick

on the corresponding HTML file you’ve already installed. Doing so helps

reinforce your understanding of each JavaScript concept described in this

book. For more information and instructions on installing the CD-ROM, see

the About the CD appendix in the back of this book.

System Requirements

Here’s what you need to get the most out of this book and the enclosed

CD-ROM:

A computer with a CD-ROM drive and a modem

A sound card (okay, this one’s strictly optional, but it’s a lot of fun!)

Windows XT[s1] or Macintosh already installed with the following:

• A Pentium or faster processor, at least 16MB of RAM, and at least

25MB of free hard drive space if you’re running Windows XT

• A PowerPC or faster processor, at least 16MB of RAM, and at least

10MB of free hard drive space for Macintosh users

• A copy of either Netscape Navigator 7.0 or Microsoft Internet

Explorer 6.0 (Chapter 1 tells you how to get a copy, if you haven’t

already)

About This Book

Think of this book as a good friend who started at the beginning, learned the

ropes the hard way, and now wants to help you get up to speed. In this book,

you can find everything from JavaScript basics and common pitfalls to answers

to embarrassingly silly questions (and some really cool tricks, too), all of which

I explain from a first-time JavaScript programmer’s point of view. Although you

don’t find explanations of HTML in this book, you do find working examples on

the companion CD complete with all the HTML you need to understand how

JavaScript works.

Some sample topics you can find in this book are:

Creating interactive Web pages

Validating user input with JavaScript

Testing and debugging your JavaScript scripts

Adapting your scripts for cross-browser issues

Integrating JavaScript with other technologies, such as Java applets,

Netscape plug-ins, and ActiveX components

Building