YUI - Yahoo User Interface Library

While there are plenty of Javascript/Ajax/CSS libraries out there, one of the best is the YUI libraries from the Yahoo Developer Network. They've got libraries for just about every major user interface component you can think of, and a little more.



The libraries are well documented, and there are also instructional videos that you can watch. The videos are also available in the iTunes store as podcasts (look for YUI Theater).

Tags: javascript, css, gui, library, freeware, open source, ajax