function openWin(url, winWidth, winHeight, winRes)
    {
      if (winRes==1) { stat="resizable=1,scrollbars=1"; }
                else { stat="resizable=0,scrollbars=0"; };
      // calculate centered window position
      winLeft = Math.round((screen.width-winWidth)/2);
      winTop  = Math.round((screen.availHeight-winHeight)/2);
      winDef = "left="+winLeft+",top="+winTop+",height="+winHeight+",width="+winWidth+",directories=no,location=no,menubar=no,status=no,toolbar=no,"+stat;
      window.open(url, "", winDef);
      return true;
    }