function detect_enter(action)
 {
  var keycode = null;

  if (action && action.which)
   {
    keycode = action.which;
   }

  else
   {
    keycode = event.keyCode;
   }

  if (keycode == 13)
   {
    document.location = "http://www.immtech.net/php/search.php";
   }
 }