function fb_onlogin() {
    FB.getLoginStatus(function (response) {
        if (response.session) {
            // logged in and connected user, someone we know
            window.location = '/FacebookAuthentication/LoginFacebook.aspx?uid=' + response.session.uid;
        }
        else {
            // logged in but not connected
            window.location = '/Register';
        }
    });	
}