Well, giving the user no way to submit the form if they have Javascript turned off is a
Bad Idea™
There's other ways to disable the enter-key-submission.
Code:
function checkKey( e )
{
var kc = ( e ) ? e.which : event.keyCode;
return ( kc != 13 );
}
<form ... onkeypress="return checkKey()" ... >
Or, include a confirmation in your validation script at the end
Code:
return confirm( "Are you ready to submit?" );
Always use JS as a backup, and let HTML do the important work.