function DoCallback(data) {
	if (window.XMLHttpRequest) {
		req = new XMLHttpRequest();
		req.onreadystatechange = processReqChange;
		req.open('POST', url, true);
		req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
		req.send(data);
		// branch for IE/Windows ActiveX version
	}
	else if (window.ActiveXObject) {
		req = new ActiveXObject('Microsoft.XMLHTTP');
		if (req) {
			req.onreadystatechange = processReqChange;
			req.open('POST', url, true);
			req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
			req.send(data);
			}
	}
}
function processReqChange() {
	// only if req show 'loaded'
	if (req.readyState == 4) {
		// only if 'OK'
		if (req.status == 200) {
		eval(what);
		}
		else {
			alert('THERE WAS A PROBLEM RETRIEVING THE XML DATA: ' );
			document.write(req.responseText);
		}
}
}