JScript to automatically retrieve / check web page

Recently I discovered a problem with Manifold WMS where if the page wasn’t accessed for a while it would cause the w3wp.exe IIS worker thread to loop. Until I find out the underlying cause I’ve written the map_keepalive.wsf script below to automatically retrieve a web page and scheduled it to run every 5 minutes. I assume something gets spun down and the concurrent WMS requests cause a problem, the map_test.asp page that this script retrieves is just a default IMS page generated from within Manifold.

  <job id="js">
     <script language="JScript">
	var finished = false;
	var timeout = 0;
	var timeoutSecs = 30;
	var forAppending = 8;
	var xmlhttp = WScript.CreateObject("MSXML2.XMLHTTP");
	xmlhttp.open("GET", "http://www.satsleuth.com", false);
	xmlhttp.onreadystatechange = function() {
		if(xmlhttp.readyState == 4)
			finished = true;
	try {
	} catch (e) {
	while ((!finished) && (timeout < timeoutSecs))
	var msg = ""
	if (!finished)
		msg = "Timeout occurred";
	else if (xmlhttp.status != 200)
		msg = "Error retrieving map_test.asp, error code: " + xmlhttp.status;
	if (msg != "") {
		var oFSO = WScript.CreateObject("Scripting.FileSystemObject");
		var oFile = oFSO.OpenTextFile("map_keepalive.log", forAppending, true);
		var dt = new Date();
		oFile.WriteLine(dt.toLocaleString() + ": " + msg);

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