A comprehensive, one page section on Ajax (XMLHttpRequest object) has just been added to the JavaScript Reference.

Performing GET and POST requests using Ajax
This tutorial explains Ajax frankly and gently, while also covering the important topics of fetching XML and JSON files using Ajax.

Animated Outline Menu
This is a sleek drop down menu that can be associated with any "anchor" link on the page. As it drops down or contracts an animated "outline" effect is applied for good measure.

Sorting an JavaScript array using array.sort()
See how to harness the sort method of JavaScript to sort an array alphabetically, numerically, or even shuffle the array elements.