50 Excellent AJAX Tutorials
This post serves as a collection of useful tutorials on working with AJAX in a wide variety of ways. You’ll find tutorials on working with forms, building shopping carts, creating chat features, working with log-ins and usernames and much more.

Link:
http://www.smashingmagazine.com/…

The Top 40 Free Ajax & Javascript Code for Web Designers
The list below is made up of the best FREE scripts available, they are all of the highest quality and more or less easy to configure.

Link:
http://speckyboy.com/2008/…

75 (Really) Useful JavaScript Techniques
Here are 75 more handy JavaScript techniques that have made websites much sleeker and more interesting.

Link:
http://www.smashingmagazine.com/…

jQuery and JavaScript Coding: Examples and Best Practices
The article will explore what constitutes best practices with regard to Javascript and, furthermore, why jQuery is a good choice of a framework to implement best practices.

Link:
http://www.smashingmagazine.com/…

Check out these posts too:

  1. 30+ Javascript/Ajax Techniques for Sliders, Scrollers and Scrollbars
  2. Design Inspiration Roundup
  3. Four more AJAX / JavaScript frameworks and code
  4. Even more jQuery samples
  5. Take Your HTML Tables to a New Level with JavaScript Frameworks
  6. Javascript based Percentage Bar / Progress Bar Creator
  7. jQuery API