$(document).ready(function(){
                $('#submit_post').click(function(){
                    var    uid         =    1;//$_SESSION['id'].val();
                    var comment        =    $('#postbox').val();
                    var pid            =    6;//$_GET['post'].val(); //static post id

                    if (!comment.trim()) {
                        //alert('Wpisz komentarz!');
                        $('#komentarzError').modal('show');
                        return false;
                    }
                    
                    $.ajax({
                        url:'/inc/functions/add-comment.php',
                        type:'post',
                        dataType:'html',
                        //data:'uid='+uid+'&comment='+comment+'&pid='+pid,
                        data : {uid: uid, comment: comment, pid: pid},
                        success:function(data){
                            if(! data ){
                                alert('Coś poszło nie tak!');
                                return false;
                            }
                            //$(data).hide().prependTo("#comment_thread").fadeIn(1000);
                            $('#comment_thread').prepend(data).fadeIn(1000);
                            //reset input boxes
                            $('#postbox').val('');
                        }
                    });
                });
            });

[PHP] pobierz, plaintext 
<script type="text/javascript" >
  var id_sesji = <?php echo json_encode($_SESSION['ID']); ?>;
</script>
[PHP] pobierz, plaintext