var how_many_ads = 9;
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads;
switch(ad) {
  case 0: content = '<a href="http://freecomputerbooks.tradepub.com/free/orm/" target=_blank><img alt="Free IT Magzines" border="0" src="/tradepub/orm468x60A.gif"></a>';
          break;
  case 1: content = '<a href="http://freecomputerbooks.tradepub.com/free/ew/" target=_blank><img alt="Free IT Magzines" border="0" src="/tradepub/ew468x60.gif"';
          break;
  case 2: content = '<a href="http://freecomputerbooks.tradepub.com/free/ew/" target=_blank><img alt="Free IT Magzines" border="0" src="/tradepub/ew468x60a.gif"></a>';
          break;
  case 3: content = '<a href="http://freecomputerbooks.tradepub.com/?pt=cat&page=Tele" target=_blank><img alt="Free IT Magzines" border="0" src="/tradepub/wbd468x60telecom.gif"></a>';
          break;
  case 4: content = '<a href="http://freecomputerbooks.tradepub.com" target=_blank><img alt="Free IT Magzines" border="0" src="/tradepub/hardocp468x60.gif"></a>';
          break;
  case 5: content = '<a href="http://freecomputerbooks.tradepub.com" target=_blank><img alt="Free IT Magzines" border="0" src="/tradepub/wbd468x60internet.gif"></a>';
          break;
  case 6: content = '<a href="http://freecomputerbooks.tradepub.com/?pt=cat&page=Tele" target=_blank><img alt="Free IT Magzines" border="0" src="/tradepub/tele468x60.gif"></a>';
          break;
  case 7: content = '<a href="http://freecomputerbooks.tradepub.com/free/swd/" target=_blank><img alt="Free IT Magzines" border="0" src="/tradepub/swd468x60.gif"></a>';
          break;
  default: content = '<a href="http://freecomputerbooks.tradepub.com/free/ddj/" target=_blank><img alt="Free IT Magzines" border="0" src="/tradepub/ddj468x60.gif"></a>';
}
end='></a>';
//if (ad < 3)
//{
document.write(content);