cant 'register' draggable/active DIV

cant 'register' draggable/active DIV

    HI, im trying to send the position of X amount of divs to a DB, my problem is, what i think, that the current  div  being dragged isn't registered. Im trying to alert 
     alert( $(this).attr("id") );
    but only receiving 'undefined'

    /C
    2. $(".flytt").draggable({ 

    4.      stop: function() {
    5.      var data_pos = $(this).position();
    6.  
    7.      $.post("save_pos.php", { id: $(this).attr("id"), x:  Math.floor(data_pos.left), y:  Math.floor(data_pos.top) }, 
    8.      function (data)
    9.      {
    10.      if (data == 1) {
    11.      alert( "Saved" );
    12.      }else{
    13.      alert( $(this).attr("id") );
    14.      }
    16.      });
    17.      }
    18.      });