我的注销脚本无效

require_once('../class.user.php');
$user_logout = new USER();


if($user_logout->is_loggedin()!="")

{
    $user_logout->redirect('login.html');
}

if(isset($_GET['logout']) && $_GET['logout']=="true")
{
    $user_logout->doLogout();
    $user_logout->redirect('login.html');
}

?>

this is my logout script logout.php,its not working,can somebody assist me please. its redirecting to a blank logout.php page with no php errors.I have a class user file with all my functions and a login.html as well as login.php for backend

If not mistaken,

if($user_logout->is_loggedin()!="") { $user_logout->redirect('login.html'); }

- is wrong.

It should be

if(empty($user_logout->is_loggedin())) { $user_logout->redirect('login.html'); } 

instead.

The purpose of the if statement:

if($user_logout->is_loggedin()!="")

Should be to logout the user if he is not logged in. It would make more sense if the if statement was:

if(!$user_logout->is_loggedin())

If you want the user who is already logged in to be logged out, then you need to access logout.php from the browser as logout.php?logout=true. This will cause the code within the second if statement to run