With the increased demand of "WEB 2.0" features such as drag 'n drop, AJAX, and client-side processing, the need for a robust javascript library in uPortal 3 becomes more and more obvious. These pages are dedicated to discussion around the many available javascript libraries*. I will focus mainly on the 6 with the most hype currently: Prototype, Dojo, Mochikit, Yahoo! UI, Google, and JQuery. Feel free to add any others which might be worth considering. For a good article reviewing some of these libraries, visit sitepoint.com.

	Prototype	Dojo	Mochikit	Yahoo!	Google	JQuery
Simple AJAX
Drag n Drop
Basic Visual Effects
Advanced Visual FX
Java integration
Event handling
Back button support with Ajax
Developer tools
Rated Features (0-4 stars)
Minimal Learning Curve
Ease of use (API)
Widget Collection (useful or not)
Documentation
Developer Community
Refined UI effect examples
Filesize Range (KB)	46-137	18-276	5-113	2-300		10-44
Licensing	MIT	AFL / BSD	MIT/AFL	BSD	Apache **	MIT
Demos	http://script.aculo.us	http://www.dojotoolkit.org/	http://www.mochikit.com/demos.html	http://developer.yahoo.com/yui/	GWT	http://www.jquery.com/demos
More Info	Prototype JS Library	Dojo JS Toolkit	Mochikit JS Toolkit	Yahoo UI Library	Google Web Toolkit	JQuery JS Library

Other JS libraries not evaluated here:

• Zimbra Ajax TK (Kabuki)
• DWR

* I will assume that the terms library, toolkit, and framework are inter-changeable. This may merit its own discussion page, just not here.
** Google offers its Java libraries under Apache license, but its Java to Javascript converter is proprietary.