In my application i am having a online exam which contains a startpage.php and in that start page whenever a user clicks on the link provided the exam starts..(The exam page consists of two frames top and bottom)Top frame is for displaying time running and bottom frame is for exam questions are displayed).
So ,whenever user starts the exam the exam page is displayed the timer starts and questions are displayed in the bottom frame but when the user clicks BACK button of the browser again the startpage.php is displayed and he can again restart his exam on clicking the link which should not happen.
first time when user starts the exam by clicking the link in startpage.php i initialized a SESSION variable and again for everytime the user enters startpage.php iam checking the session variable whether it is initialized or not.If it is initialized then it means the exam had already started so iam redirecting to error page if not initialized the exam starts.
What i tried is working if i try to open the startpage.php in another tab of the same browser after once he started the exam but it is not working if i click BACK button...
And correct me if my approach is not correct??
any suggestion ??? Thanks in advance...