function addEvent(elem, evtType, func)
{
   if (elem && typeof(elem) == "object")
   {
      // first try the W3C DOM method
      if (elem.addEventListener)
      {
         elem.addEventListener(evtType, func, false);
      }
      // otherwise use the 'traditional' technique
      else
      {
         elem["on" + evtType] = func;
      }
   }
}