/*
 * ajax.js
 *
 * functions to handle ajax calls
 *
 * from "Javascript in 24 Hours" by Michael Moncur
 */
 
var ajaxreq = false, ajaxCallback;

function ajaxRequest(filename)
{
	try
	{
		/*
		 * Most browsers
		 */
		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();
	} else {
		alert("Request failed: " + ajaxreq.statusText);
	}
	
	return true;
}