You should have tried a search on optional prompts this has been discussed lots of times.
Heres a recent discussion:-
https://bobj-board.org/t/113811/6
Mak 1 
(BOB member since 2005-01-06)
You should have tried a search on optional prompts this has been discussed lots of times.
Heres a recent discussion:-
https://bobj-board.org/t/113811/6
Mak 1 (BOB member since 2005-01-06)