// global variables to keep track of teh request
// and the function to call when done

var ajaxreq = false, ajaxCallback;

// ajaxRequest: Sets up a request

function ajaxRequest(filename) {
	try {
		// Firefox / IE7 / Others
		ajaxreq = new XMLHttpRequest();
	} catch (error) {
		try {
			// IE 5 / IE 6
			ajaxreq = new ActiveXObject("Microsoft.XMLHTTP");
		} catch (error) {

			return false;
			
		}
	}
	ajaxreq.open("GET", filename);
	ajaxreq.onreadystatechange = ajaxResponse;
	ajaxreq.send(null);
}

// ajaxResponse: Waits for response and calls a function

function ajaxResponse() {
	if(ajaxreq.readyState != 4) return;
	if(ajaxreq.status == 200) {
		// if the request succeeded...
		if(ajaxCallback) ajaxCallback();
	} else alert("Request failed: " + ajaxreq.statusText);
	return true;
}