how to disable the button when submitted

Question

Hi 
every one.
I have a usercontrol and i populate it in modalpoup. which contains Save button and this button validates the all controls .if i click on save button it should save the record in the DB.But i have a problem here , i am able to click the save button more than once this time duplicate records are inserted. can any one help me how to prevent the double clicking of the Button. 

Help me plz