function getXmlHttpObject() {
	var xRequest=null;
	if (window.XMLHttpRequest) {
		xRequest=new XMLHttpRequest();
	}else if(typeof ActiveXObject != "undefined") {
		xRequest = new ActiveXObject("Microsoft.XMLHTTP");
	}
	return xRequest;
}

function callbackWithResponse(callback, xmlHttp){
	if (xmlHttp.readyState == 4 || xmlHttp.readyState == "complete") {
		response = xmlHttp.responseText;
		if(response != "") {
			var call = callback+"(\""+response.substr(1)+"\");";
			eval(call);
		}
	}
}

function getSubscriptionResponse() {
	var xmlHttp = getXmlHttpObject();
	if (xmlHttp == null) return;
	
	var subscribe = 0; //unsubscribe
	if(document.getElementById('subscribe').checked == true)
		subscribe = 1; //subscribe
		
	var url = "http://www.patchingzone.net/list/subscribe.php?address=" +
					document.getElementById('address').value +
			  "&subscribe=" + subscribe;
	xmlHttp.onreadystatechange = 
			function() { callbackWithResponse("handleSubscriptionResponse", xmlHttp); };
	xmlHttp.open("GET",url,true);
	xmlHttp.send(null);
}

function handleSubscriptionResponse(response) {
	document.getElementById('responseDiv').innerHTML = response;
}