/*******************************************************************************
*      Script: ajax.js
* Description: java script routines to support AJAX for the IYFRSF web page
*               This is included in pagetop.php to initalize ajax.
*    Comments: Intilectual property of Clint Collier: on loan to iyfr.
*     Created: 05/27/2008 [CLC]
*    Modified: 
*******************************************************************************/

//******************************************************************************
// Make an AJAX XMLHTTP object
//******************************************************************************
function getXMLHTTPRequest(){
var request = false;
try {
	request = new XMLHttpRequest(); // Mozilla (Firefox, Netscape) & IE7
}
catch(err1) {
	try {
		request = new ActiveXObject("MSXML2.XMLHTTP"); // current versions of IE
	}
	catch(err2) {
		try {
			request = new ActiveXObject("Microsoft.XMLHTTP"); // earlier versions of IE
		}
		catch(err3) {
			request = false;
		}
	}
}
return request;
} //getXMLHTTPRequest

var myAjaxRequest = getXMLHTTPRequest();


//******************************************************************************
// Send a year back to the server to request a new list of newletters
//******************************************************************************
function AjaxGetYearList(year) {
	// to prevent browser caching, append a random number to our request
	var randomno = parseInt(Math.random()*99999999);
	var url = "ajaxgetyearlist.php?newsletteryear="+year+"&random="+randomno;
	document.getElementById('newsletterlistarea').innerHTML = "<I>Retrieving issues...</I>";
	myAjaxRequest.open("GET",url,true);
	myAjaxRequest.onreadystatechange = AjaxNewYearList;
	myAjaxRequest.send(null);
} //AjaxGetYearList


//******************************************************************************
// Populate our new list of newletters when returned from the server
//******************************************************************************
function AjaxNewYearList(){
	if (myAjaxRequest.readyState == 4) {
		if (myAjaxRequest.status == 200) {
			document.getElementById('newsletterlistarea').innerHTML = myAjaxRequest.responseText;
		} else {
			alert ("Ajax Error: " + myAjaxRequest.status + " " + myAjaxRequest.statusText);
		}
	}
} //AjaxNewYearList