Javascript is the primary client-side scripting language for the web. Javascript is the only really optional language on your site, but some clever designers have utilized Javascript to change things you simply couldn't do with just HTML.

Like the CSS and HTML guides, we're not going to go into detail about how Javascript works, but we will direct you to some means of learning Javascript.

Web: W3 Schools Javascript Tutorial
Learn Javascript

Web: W3 DHTML Tutorial
DHTML (or Dynamic HTML) is the means by while a user will hide, show, move, and otherwise change the layout of a page after the page is loaded.

Book: Dynamic HTML, the Definitive, Guide
While this book is called "Dynamic HTML", it's worth knowing that DHTML is the primary bit of Javascript most designers will utilize when building the layout of their site.

Book: Javascript and DHTML Cookbook
The O'Reilly "Cookbooks" usually include big chunks of code to do specific clever things. It's not the best for learning, but it does give you a good idea of what can be done.

Incoming Guide Links Intro to the Advanced Layout Options Layout Guide

Outgoing Guide Links CSS HTML

Easy Link BBCode Link: [guide=Javascript]Javascript[/guide] URL: http://dkpsystem.com/guide/Javascript

BBCode Guide