The Day function in ASP lets you find out what day in the current month it is. If the current date is January 3, then the Day function will return 3.

So, for example if you have a StartDate variable and want to extract just the day part, you would say

StartDay = Day(StartDate)

StartDay would then be equal to the value 3.

Make sure, of course, that StartDate is actually a date value :)

ASP Date Functions