var banneridx = 100000;

function nextbanner()
{
  var banner = document.getElementById('banner'+banneridx);
  if(banner)
  {
    banner.className = banner.className.replace(/\s?topbanner/g, "");
  }
  banneridx++;
  banner = document.getElementById('banner'+banneridx);
  if(!banner)
  {
    banneridx = 1;
    banner = document.getElementById('banner'+banneridx);
  }
  if(banner)
  {
    banner.className += " topbanner";
  }
}

function external_links()
{
  nextbanner();
  var links = document.getElementsByTagName('a');
  for(var l in links)
  {
    if(links[l].href && links[l].getAttribute("rel") == "external") links[l].target = "_blank";
  }
}

setInterval(nextbanner, 10000);
if(window.addEventListener) window.addEventListener("load", external_links, null);
else window.attachEvent("onload", external_links);