function FB_Logout(url, sessionCookie) {
    alert('here');
    FB.ensureInit(function() {
        FB.Connect.logout(function() {
            var name = sessionCookie;
            document.cookie = name + '=;expires=Thu, 01-Jan-1970 00:00:01 GMT';
            url = (url + (url.indexOf('?') > -1 ? '&' : '?') + (new Date()).getTime());
            document.location = url;
        });
    });
}