jQuery with <TEXTAREA> manipulation

jQuery with <TEXTAREA> manipulation

Hi ,
I am trying to do datavalidation in TEXTAREA onkeyup.But some reason it is not wokrking, and no error.
Please help me here what went wrong.. Nothing is returning....

  1. <script type="text/javascript" src="./js/jquery-1.4.2.js"></script>
  2. <script type="text/javascript">
  3.   var oldval = $('textarea').val();
  4.     $('textarea').live('onkeyup', function() {
  5.        if($(this).val() != oldval) {
  6.          $('textarea').val(oldval + ',');
  7.        }
  8.         });
  9. </script>

JSP:
  1. <TEXTAREA NAME="dynamicitem" COLS="8" ROWS="9"  ></TEXTAREA>