here some java:
http://javaalmanac.com/egs/java.util/pkg.html

and javascript:
http://www.merlyn.demon.co.uk/js-date0.htm

and once again the Java Code Conventions.

And here is a patched version of the Date-Object in AntvilleLib:

antvillelib.1.4.date.patched.js (js, 6 KB)

which extends Date.prototype.getTimespan to return the .age as part of the result object containing:
.years
.months
.days
.minutes
.seconds
.milliseconds
.absMonths
.absDays
.absMinutes
.absSeconds
.absMilliseconds


and adds:
Date.prototype.isLeapYear
returns true or false for this Date

Date.prototype.getStarSign
returns an english String

Date.prototype.splitValues
returns an Object containing (integer values)
.year
.month
.day
.minute
.second
.millisecond