note 22465 added to function.session-start

I try to initialize form data by session . I use session_start() to initialize session. When the form is posted then i hit back button , the data entered in the form was cleared . How to fix this problem ? It isn't occured if I don't use session_start() . -- http://www.php.net/manual/en/function.session-start.php http://master.php.net/manage/user-notes.php?action=edit+22465 http://master.php.net/manage/user-notes.php?action=delete+22465 http://master.php.net/manage/user-notes.php?action=reject+22465