fb.comments does not showing Log out link

here is my code

< fb:comments xid="mahfuz" canpost="true" candelete="false" >

< /fb:comments>

here is JS SDK code

<div id="fb-root"></div>
<script type="text/javascript">
  window.fbAsyncInit = function() {
    FB.init({appId: 'my app id', status: true, cookie: true,
             xfbml: true});
  };
  (function() {
    var e = document.createElement('script'); e.async = true;
    e.src = document.location.protocol +
      '//connect.facebook.net/en_US/all.js';
    document.getElementById('fb-root').appendChild(e);
  }());
</script>