Resources

Tutorials

• JavaScript Tutorial - W3Schools
• Voodoo's Intro to JavaScript
• JavaScript tutorial - DOM nodes and trees

OOP

• OOP in JS, Part 1: Variables and Methods
  
• OOP in JS, Part 2: Inheritance

• Object Hierarchy and Inheritance in JavaScript

Ajax

• Ajax:Getting Started - mozilla.org
• Ajax Tutorial - w3schools.com

• Ajax & XMLHttpRequest - French-to-English translation

Sun Microsystems

• Client-Side JavaScript Guide
• Client-Side JavaScript Reference

Frameworks

• jQuery
• Sizzle
• Prototype
• script.aculo.us
• MooTools
  

Misc

• JavaScript Closures for Dummies
  
• Browser detection