var preloadimages=new Array("bg1","bg2","bg3","bg4","bg5","bg6","bg7","bg8","bg9");
if (navigator.appName == "Microsoft Internet Explorer") 
{
document.body.style.background="url('images/"+
preloadimages[Math.floor(Math.random() * preloadimages.length)]
+".jpg') fixed white center no-repeat";
};