Validation for Dynamic Controls

Hi Friends,

This is ram. i am facing problem with dynamic control validation.

I am creating a timesheet in which i am creating runtime controls on a selected dates between two date like From Date 10-01-2008 to 15-01-2008...

in which i am creating run time time text box in that i am entering reg.hrs and OT values aacording to date and i want user shold only enter number and dolues like 10.23 or 10 he should not able to enter  any othe values like character and special caracter.

for ex.

Date                      Reg. Hrs           OT                   Total

10-01-2008             10    & ...