First fogiver me about my poor english !
 What I want is How to kown For example If customer chose January I know it has 31 days If customer chose February I know it has 28 days
and so on......
Thank for your help .

If you want to know the last day of the previous month, you use something like this: DateSerial(2004, 3, 0)

In this case, you get the date 29 February 2004

If you use this: DateSerial(2004, 9, 0)

you get 31 August 2004. Try it.



Greg Serrano
Michigan Dept. of Environmental Quality, Air Quality Division

You can also check out this Website: http://mvps.org/access/datetime/date0007.htm

This gives great examples that help when you do not want to limit the code to just the previous month. This is from an Access point of view but the code works in VB as well.

Kenny Alligood