back problem

[Anon]

Hi. My php code generates a 20-question test from a mysql database. User answers these questions and, in the next page, sees the number of wrong and right answers, and this numbers are recorded in the database for future analysis. However, i don't want the user to go back (by using browser's back button for example) and post the answers again and again. Once he/she submits, it's over, no going back.
How can i prevent the user from going back ?

[[deleted]]

"How can i prevent the user from going back?"

You can't.
The only thing you can do is force the user to register by entering his/her details. Then you can store those details on the server, and every time someone submits the answers, you can check that data to see if he/she has already submitted answers.
If they have, you can send a message.
If they haven't, you can process the answers and update the userdata to say "has submitted answers"

You coul try setting a cookie on the client after submitting, but that it is very easy to remove the cookie, or to move to a different computer and submit again.

[Anon]

sessions. Try starting a session with the very first page, and then updating the pagenumber as the user advances through the test. If a previous page is called,

header("Location: errorpage.php");