//Logout  page code
                                     $pdo_crud = new PDOCrud();
                               
                                     //set session variables - 1st parameter is the session variable name and 2nd is value to be matched in database table
                                     $pdo_crud->unsetUserSession("userName");
                                     //or you can unset all user session variable set by setUserSession function
                                      $pdo_crud->unsetUserSession();