Javascript

Introduction by Author

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.

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 intelligent Web pages with JavaScript can be overwhelming — if you let it. You can do so much with JavaScript! To keep the deluge to a minimum, this book concentrates on the practical considerations you need to get your interactive pages up and running in the least amount of time possible.

How This Book Is Organized

This book contains five major parts. Each part contains several chapters, and each chapter contains several sections. You can read the book from start to finish if you like, or you can dive in whenever you need help on a particular topic. (If you’re brand-new to JavaScript, however, skimming through Part I first sure couldn’t hurt.) Here’s a breakdown of what you can find in each of the five parts.

Part I: Building Killer Web Pages for Fun and Profit

This part explains how to turn JavaScript from an abstract concept to some­thing happening on the screen in front of you. It takes you step by step through obtaining your choice of Netscape Navigator or Microsoft Internet Explorer, discovering how to access and modify the document object model, and writing and testing your first script. Part I also includes an overview of the JavaScript language itself.

Part II: Creating Dynamic Web Pages

In this part, I demonstrate practical ways to create Web pages that appear differently to different users. By the time you finish Part II, you’ll have seen sample code for such common applications as detecting your users’ browsers on-the-fly, formatting and displaying times and dates, and storing information for repeat visitors by using cookies.

Part III: Making Your Site Easy for Visitors to Navigate and Use

The chapters in Part III are devoted to helping you create Web pages that visi­tors can interact with easily and efficiently. You find out how to use JavaScript’s event model and function declaration support to create hot buttons, clickable images, mouse rollovers, and intelligent (automatically validated) HTML forms.

Part IV: Interacting with Users

JavaScript is evolving by leaps and bounds, and Part IV keeps you up-to-date with the latest and greatest feats you can accomplish with JavaScript, including brand-new support for dynamic HTML and cascading style sheets. In this part you also find a double handful of the most popular JavaScript and DHTML effects, including pull-down menus, expandable site maps, and custom tooltips.

Part V: The Part of Tens

The concluding part pulls together tidbits from the rest of the book, organized in lists of ten. The categories include great JavaScript-related online resources, common mistakes, and debugging tips.

Part VI: Appendixes

At the back of the book you find a handful of indispensable references, includ­ing JavaScript reserved words, color values, document objects, and special characters. There’s also a nifty how-to section that describes all the cool tools you find on the companion CD.
Read comments for more