Beginning HTML, XHTML, CSS, and JavaScript®

Chapter 12. Working with JavaScript

You learned the key concepts behind the JavaScript language in Chapter 11; in this chapter, you see how these concepts come together in working scripts. By looking at several examples, you learn different ways in which JavaScript can interact with your web pages, some helpful coding practices for writing your own JavaScripts, and some shortcuts to creating interactive pages. The chapter is roughly split into two sections:

• Creating your own basic scripts: The first section focuses on how to write your own basic scripts. Most of these examples work with form elements.

• Using pre-written JavaScript libraries: The second section focuses on a number of scripts that have already been written and shows you how you can add powerful and complex features to your site with just a few lines of code.

By the end of the chapter, not only will you have learned a lot about using JavaScript in your pages, but you will also have seen many helpful tools and techniques you can use in your own pages.

Practical Tips for Writing Scripts

Before you start looking at the examples, I'd like to share a few practical hints on developing JavaScripts that should save you time.

Has Someone Already Written This Script?

There are thousands of free JavaScripts already on the Web, so before you start writing a script from scratch, it is worth searching to see if someone has already done all the hard work for you. Here are a couple of sites that will help you get going (and don't forget you ...