Facebook logout redirection not working

I am currently trying to implement facebook login/logout on my website. However, I have an issue with redirections, I wrote :

FB.Event.subscribe('auth.login', function () {
        window.location = '/loginfb';
    });
    FB.Event.subscribe('auth.logout', function () {
        window.location = '/logoutfb';
    });

in window.fbAsyncInit = function() { ... } after FB.init

The problem is that when i logout, my site redirects to the loginfb url. Where could that come from?