This applet is from the compact disk that accompanies the book Calendrical
Calculations: The Millennium Edition by Edward M. Reingold and
Nachum Dershowitz (Cambridge University Press, second printing, 2002).
It can still be run with CheerpJ Applet Runner under Chrome.
For more
information, and any errata, see the site
http://www.calendarists.com.
For details about these dates, click here.