I think there's a problem with:
code:
xmlhttp.send(Math.round(Math.random()*99999));
because a "normal" GET query looks like "key=value&this=that", although I know that "page.php?81256" should work too...
Although, there's a much better way to make sure that the downloaded file is always the latest version from the server. The Win32 API function "DeleteUrlCacheEntryW" will make sure that the cached version of the requested page is removed before you execute the XmlHttp request.
code:
var sUrl = "http://arkanes-arkade.co.uk/XBox/ScriptVersion.txt";
Interop.Call('wininet.dll', 'DeleteUrlCacheEntryW', sUrl); //Clear URL from cache
var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
xmlhttp.open("GET", sUrl, true);
xmlhttp.send();