MANUALLY EXPIRE THE SESSION人工地使SESSION过期The last thing to do is manually "expire" the session, or at least a portion of it. In my case, I wanted the session to stay alive, so I could not use session_unset() or session_destroy(). However, I didn‘t want the user to go back to the previous pages and change things. Remember that $_SESSION["alive"] variable? After the final submit, all we have to do is get rid of it. There are two ways to do this: