general question...

Using php3 is there a way to have a page only be access if the user is coming from another page? I don't quite know how to word what I am thinking but for instance... Form <-- page that contains a form to submit an email address to a mailing list Confirm <-- page that confirms the users email address Submit <-- page that connects to database and submits users email address What I want to do is have users not be able to access the submit page unless they are refered from the confirm page... Using php is this possible? And if so could someone point out somewhere that has more info so I may begin incorporating this into my scripts. Thanks in advance... Jas