// ----------------------------------------------------------------------------
//  StartBlinking -- Force the given element to blink in a specified period
//     (in milliseconds).
// ----------------------------------------------------------------------------
   function StartBlinking(nPeriod, idElm, csClass1, csClass2)
   {
      try
      {
         setInterval("BlinkCallback('" + idElm + "', '" + csClass1 + "', '" + csClass2 + "')", nPeriod);
      } catch (e) {}
   }


// ----------------------------------------------------------------------------
//  BlinkCallback -- Blink functionality callback function.
// ----------------------------------------------------------------------------
   function BlinkCallback(idElm, csClass1, csClass2)
   {
      try
      {
         var eElm = obj(idElm);

         if (eElm != null)
         {
            if (eElm.className == csClass1)
                eElm.className =  csClass2;
            else
                eElm.className =  csClass1;
         }
      } catch (e) {}
   }