"The code listens to DataTable's own cellMouseoverEvent and cellMouseoutEvent and handles its own timers to show and hide the tooltip. There is only one Tooltip for the whole of the DataTable which is set on the fly when the cursor remains for half a second on any cell in the Item column. The text for the Tooltip is taken from the extra filed in the Record object which is not displayed and the location is also calculated from the cursor coordinates when the event was triggered."

"YUI Test is a testing framework for browser-based JavaScript solutions. Using YUI Test, you can easily add unit testing to your JavaScript solutions. While not a direct port from any specific xUnit framework, YUI Test does derive some characteristics from nUnit and JUnit."

Effective use of YUI, JSON, XHR, etc.

YUI 3 preview release. Not backwards compatiable with YUI 2. Smaller footprint, animation is greatly improved... Grids doesn't seem to have changed much. Not sure about anything else yet.

This extension transforms top-level MediaWiki headers into tabs using Yahoo! YUI library.

lots of examples, documentation seems good and there's a bit on PHP+YUI too.