Deatroys all data registered to a session.
To kill a session we used session_destroy and session_unset().
But both are having diffrent meaning.
1. session_destroy is more effrctive than session_unset. session_destroy destroy session.
session_destroy() is use to kill the session.
2. session_unset only clear session but session also remain in computer.it just remove all session
variable.it not remove session.
session_unset() in used to kill the session.