Javascript

irt.org

An excellent repository of javascript knowledge. What started out as a comp.lang.javascript FAQ has evolved into one of the most useful javascript sites on the Internet. Superbly organized.

Magic Buttons

This tutorial will teach you how to make javascript mouseovers and clickable buttons for use in your web pages.

GateKeeper

The GateKeeper is a cool chunk of JavaScript code that anyone can use to restrict access to some or all of their web pages without the need for CGI scripting or server based authentication methods.

Voodoo's Intro to JavaScript

Excellent ground floor tutorial on JavaScript. Will definitely help the novice get a handle on some basic JS.

WebCoder.com

A very professional site with very hight quality content. Plenty of javascripts and tutorial pages.

Netscape's Javascript documentation

A must have reference for any javascript developer. Both the Javascript Guide and the Javascript Reference are downloadable so you can use them offline. (You'll want the client side JS Guide & Reference)

JavaScript for the Total Non-Programmer

This well done tutorial takes you by the hand and teaches some basic JavaScript principles. Plenty of hands-on learning here.

Timothy's JavaScript Examples

Many many JS effects demonstrated. Animated menus, color pickers, alert/confirm boxes and more. Be sure to check out his list of even more JavaScript resources.