code libraries
Of course you know how to write it yourself, but if somebody's already done the hard work, why not just copy and paste? (some tweaking may be required too)
yui - the yahoo user interface library
The Yahoo! User Interface (YUI) Library is a set of utilities and controls, written in JavaScript, for building richly interactive web applications using techniques such as DOM scripting, DHTML and AJAX. The YUI Library also includes several core CSS resources. All components in the YUI Library have been released as open source under a BSD license and are free for all uses. Click Here to visit yui (website opens in new window).adobe labs spry framework for ajax
The Spry framework for Ajax is a JavaScript library for web designers that provides functionality that allows designers to build pages that provide a richer experience for their users. It is designed to bring Ajax to the web design community who can benefit from Ajax, but are not well served by other frameworks. Click Here to visit Adobe Labs (website opens in new window).script.aculo.us
script.aculo.us provides you with easy-to-use, cross-browser user interface JavaScript libraries to make your web sites and web applications fly. Click Here to visit script.aculo.us (website opens in new window).mini ajax
A showroom of nice looking simple downloadable DHTML and AJAX scripts. Click Here to visit MiniAjax.com (website opens in new window).eric meyer toolbox
A collection of tools, plugins, and other hacks that Eric Meyer has put together. In most cases, these are solutions to problems he faced, or else enhancements that he wanted but couldn't find elsewhere. If they're useful to you, great! Have a blast. Click Here to visit MeyerWeb (website opens in new window).
dzone
Simpy
Yahoo MyWeb