Очистить текстовую область

В событии Onselect у меня есть сценарий:

$("#vinanghinguyen_images_bbocde").val('');
$("#vinanghinguyen_images_bbocde").val(vinanghinguyen_final_bbcode);

Я хочу, чтобы чистая текстовая область id =" vinanghinguyen_images_bbocde "добавляла к ней значение. Но textarea add add add add add and value, а не Я хочу очистить его перед добавлением значения

Я использую uploadify, вот моя функция

<script type = "text/javascript" >
  $(document).ready(function() {
    vinanghinguyen_bbcode = '';
    vinanghinguyen_final_bbcode = '';
    vinanghinguyen_link = '';
    vinanghinguyen_final_derect_link = '';
    response = '';

    $('#file_upload').uploadify({
      'uploader'  : '{SITE_FULL_URL}/uploadify/uploadify.swf',
      'script'    : '{SITE_FULL_URL}/uploadify/uploadify.php',
      'cancelImg' : '{SITE_FULL_URL}/uploadify/cancel.png',
      'folder'    : 'data/picture_upload/2011',
      'auto'      : false,
      'multi'     : true,
      'buttonText': '',

      'onComplete': function(event, ID, fileObj, response, data) {
        vinanghinguyen_bbcode = '[IMG]' + 'http://cnttvnn.com' + response + '[/IMG]' + '\n';
        vinanghinguyen_final_bbcode = vinanghinguyen_final_bbcode + vinanghinguyen_bbcode;
        vinanghinguyen_derect_link = 'http://cnttvnn.com' + response + '\n';
        vinanghinguyen_final_derect_link = vinanghinguyen_final_derect_link + vinanghinguyen_derect_link;

        $("#vinanghinguyen_images_bbocde").val('').val(vinanghinguyen_final_bbcode);
      //$("#vinanghinguyen_images_derect_link").val(vinanghinguyen_final_derect_link);
        $("#vinanghinguyen_result").show();
        $(".uploadifyQueue").height(5);
      },

      'onSelect': function(event, ID, fileObj) {
        $("#vinanghinguyen_images_bbocde").val('');
        $("#vinanghinguyen_result").hide();
        $(".uploadifyQueue").height(315);
      },
    });
  });
</script>