$error = true;
         header("Location: ../index.php?login_error=empty");
     } else {
         if (!validateText($user, 2, 20)) {
             $error = true;
             header("Location: ../index.php?login_error=user");
         } else {
             if (!validateText($userPassword, 10, 50)) {
                 $error = true;
                 header("Location: ../index.php?login_error=pw");
             } else {
                 if (!$db->userExists($user)) {
                     $error = true;
                     header("Location: ../index.php?login_error=nonexistent");
                 } else {
                     if (!$db->checkPassword($user, $userPassword)) {
                         $error = true;
                         header("Location: ../index.php?login_error=wrongpw");
                     }
                 }
             }
         }
     }
     if (!$error) {
         $_SESSION['username'] = $user;
         $_SESSION['db'] = $db;
         $_SESSION['user'] = new User($user);
         // success!
         header("Location: ../index.php");
     }
 }