next tab indexed button should be set as default button.

My Doubt is as follows:

i had a Asp page with only table( ) it contains  both resistration page  and Login page design. it contains total 2 submit buttons one in registration and other in login . when values entered in all the feilds of registration and pressing Enter key the next tab indexed button event should rise. can anyone help for this Please.

same for login, if i have entered username and password and press enter next tab indexed event should rise.