Book excerpt: JavaScript is an essential language for creating modern, interactive websites, but its complex rules challenge even the most experienced web designers. With JavaScript: The Missing Manual, you'll quickly learn how to use JavaScript in sophisticated ways -- without pain or frustration -- even if you have little or no programming experience. JavaScript expert David McFarland first teaches you the basics by having you build a simple program. Then you'll learn how to work with jQuery, a popular library of pre-built JavaScript components that's free and easy to use. With jQuery, you can quickly build modern, interactive web pages -- without having to script everything from scratch! Learn how to add scripts to a web page, store and manipulate information, communicate with the browser window, respond to events like mouse clicks and form submissions, and identify and modify HTML Get real-world examples of JavaScript in action Learn to build pop-up navigation bars, enhance HTML tables, create an interactive photo gallery, and make web forms more usable Create interesting user interfaces with tabbed panels, accordion panels, and pop-up dialog boxes Learn to avoid the ten most common errors new programmers make, and how to find and fix bugs Use JavaScript with Ajax to communicate with a server so that your web pages can receive information without having to reload