Forums Scripts & Popups working with dates before Jan 1 1970

I have a script which needs to be able to calculate a person's age based on the date entered for a date of birth. Using
set %age $calc($asctime($ctime($today),yyyy)-$asctime($ctime(%dob),yyyy))
works fine for dates on or after Jan 1 1970
any suggestions as to how I can do something similar for dates before Jan 1 1970?
The date of birth is not entered in any one specific format.

the big problem with that is of course using the identifiers $ctime and $asctime which are based on the elapsed seconds since Jan 1 1970.
to do what you want you will have to work out a way to compute the calendar yourself.
web page with some information

Thanks..too bad $ctime(text) won't give a negative number if the date (in text) was before Jan 1 1970

Problems resolved...not as easily or simply as I would've liked (ie: getting a negative number when using $ctime with a date before Jan 1 1970, rather than $null), but I have managed to get around the problem. Thanks to all that helped.