Here is an example of a CWP website that implements a slightly modified version of the YUI autocomplete code. You may try with search terms such as genome, botany, or nano. Starting from the third character typed in the search bar, a drop down menu with suggestions appears. You can select a suggestion either with arrow keys or with the mouse, and hit enter or click to copy it to the search bar. The database queried for autocomplete holds about 65'000 suggestions.

In the course of constructing this feature I went through three iterations: First I tried a fast and short code that however is not free; then I switched to the prototype and Rico libraries, which are free, but had some browser compatibility issues and are quite bloated (in KB); finally I landed at YUI.

I see that the AJAX subforum is not very active up to now, and would like to propose the following so that others and the forum can get momentum: I'm asking those that are already proficient in AJAX and CWP to help create in this subforum a chart of AJAX libraries, list their features and functions, and their advantages and drawbacks.

Let's start by gathering some URLs:

Prototype - http://www.prototypejs.org/

Rico - http://openrico.org/

script.aculo.us http://script.aculo.us/

YUI - http://developer.yahoo.com/yui/

Oh yes, and this excellent plugin for FireFox really helped me to debug my solution: FireBug

... Well even though this post is kind of dead:

JQuery - http://jquery.com/

Mootools - http://mootools.net/

JQuery is really the main competitor to Prototype, though which you use is generally up to personal preferences. Mootools is more of an interface library but was originally an add on for prototype - like script.aculo.us is now. Mootools now runs its own library - based on prototype, but all contained in 1 library.

Note that you cannot use Mootools and Prototype together, while you can use JQuery (which provides the same functionallity) with Mootools and other tools that would conflict with Prototype.