Facebook-connect : Can't logout using PHP SDK   JS SDK
<?
//uses the PHP SDK.  Download from https://github.com/facebook/php-sdk
require 'src/facebook.php';
$facebook = new Facebook(array(
  'appId'  => 'ddddd',
  'secret' => 'ddddddddddddddd',
));

$userId = $facebook->getUser();

?>
 <?php if ($userId) {
      $userInfo = $facebook->api('/' + $userId);
      $params = array('next' => 'http://www.nofrenchtouch.com/include/logout.php');
      $logout = $facebook->getlogoutURL($params);?>

      <span class="facebook-in">Bienvenue <?= $userInfo['name']?> - <a href="#" onClick="logoutUser(); return false;" class="facebook-bt"> Se déconnecter</a>
</span>
    <?php } else { ?>
    <div id="fb-root"></div>
    <a href="#" class="facebook-bt" onClick="loginUser(); return false;">Se connecter avec Facebook</a>
    <?php } ?>


<script>
          window.fbAsyncInit = function() {
        FB.init({
          appId: '<?php echo $facebook->getAppID() ?>',
          cookie: true,
          xfbml: true,
          oauth: true
        });
        FB.Event.subscribe('auth.login', function(response) {
          window.location.reload();
        });
        FB.Event.subscribe('auth.logout', function(response) {
          window.location.reload();
        });
      };
      (function(d){
         var js, id = 'facebook-jssdk'; if (d.getElementById(id)) {return;}
         js = d.createElement('script'); js.id = id; js.async = true;
         js.src = "//connect.facebook.net/fr_FR/all.js";
         d.getElementsByTagName('head')[0].appendChild(js);
       }(document));

       function loginUser() {
    FB.login(
        function(response) {
            getStatus(); //This is a call to a different function...
        },
    {scope:'email,publish_stream, user_birthday, friends_birthday'}
    );

     function logoutUser() {
    FB.logout(
        function(response) {
        }
    );
}
</script>

<a href="javascript:FB.logout();void(0)">Log Out</a>

function logoutUser() {
    FB.logout(
        function(response) {
//Pass control to function in php where you can destroy your session and cookies.
// windows.location=PHP function
        }
    );