var ajaxreq=false, ajaxCallback;
function ajaxRequest (filename) {
	try {
		ajaxreq= new XMLHttpRequest();
	} catch (error) {
		try {
			ajaxreq= new ActiveXObject ("Microsoft.XMLHTTP");
		} catch (error) {
			return false;
		}
	}
	ajaxreq.open("GET", filename);
	ajaxreq.onreadystatechange = ajaxResponse;
	ajaxreq.send(null);
}

function ajaxResponse() {
	if (ajaxreq.readyState != 4) return;
	if (ajaxreq.status == 200) {
		if (ajaxCallback) ajaxCallback();
	}
	return true;
}