A bug was found that was miscalculating the day of the week (Thx Leon for finding it). Additionally I set the minimum year to 1582 to align with the creation of the Gregorian calendar.
I’ve fixed the bug and posted the new release on the DHTML Calendar page.

February 29th, 2008 at 10:46 am
Hello,
The DHTML calander still show’s the wrong dag names.
Today (29-02-08) it’s Fri but the calander say that its Sat.
Hope you can fix this ;-)
Andries