can't store cookies after user sends facebook request

I have some strange behavior with a Facebook request

My application allows users to send application requests to their friends.

When I proc开发者_JAVA百科ess the call back I can't seem to read or write any of the session objects I set prior to or after this act.

What does Facebook do to my session objects?

I found it on another post

 $.ajaxSetup({
          beforeSend: function(xhr) {
                                    xhr.setRequestHeader('X-CSRF-Token',
$('meta[name="csrf-token"]').attr('content'));
                                         }
              });