datetime.diff()
Determines the number of given date parts between two different dates
datetime.diff( datePart=string, date1=datetime )
Returns: Number
Examples
date = createDateTime(1997,04,11);
echo( date.Diff("d", "1997-04-25") & "<br>"); // 1
dateOne = createDate(1997,04,11);
echo( dateOne.Diff("d", "1997-04-11") & "<br>"); // 0
datetime = createDateTime(1992,12,11,01,00,00);
echo( datetime.Diff("h", "1992-12-11 00:00:00") & "<br>"); // -1