Calculate 'UTC seconds' (sometimes also called 'epoch seconds' or 'unix seconds') as the number of seconds since at 01-01-1970 00:00:00 for the
GMT date/time provided. Will also allow you to enter UTC seconds or daynumber and compute
the approriate GMT date/time and yearday fields.
Note1: If an invalid date such as Apr'31 is entered, UTCcalc will compute UTC seconds
for May 1st. The select list fields are updated to reflect the correct representation of
Note2:UTCcalc will not handle dates before 01-Jan-1987 00:00:00
Note3:UTCcalc will not work with Netscape 3.x - (missing date.getUTCFullYear() function).
This is version: 2.4 16-Sep-2005