Ajax Noob here....

when I run this code, when the readyState is 4, the ready status is 0. I'm not sure what i'm doing wrong... TIA

//claim.js
function sendRequest(request, url){
	request.open("GET", url, true);
	request.onreadystatechange = updateCase;
	request.send(null);
}

function clearCase(){
	var url = "clearCase.php";
	sendRequest(request1, url);
}

function updateCase(){
	//alert(request1.readyState);
	if (request1.readyState == 4) {
		response = request1.responseText;
		if (request1.status == 200) {
			alert('cleared!');
		} else {
			alert(request1.status + 'not cleared');
		}
		request1 = createRequest();
	}
}

Code (markup):

//ajax.js
function createRequest() {
	var request = null;
	try {
		request = new XMLHttpRequest();
	} catch (trymicrosoft) {
		try {
			request = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (othermicrosoft) {
			try {
				request = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (failed) {
				request = null;
			}
		}
	}
	if (request == null) {
		alert("Error creating request object!");
	} else {
		return request;
	}
}

var request1 = createRequest();

Code (markup):

//clearCase.php
<?php session_start();
	unset($_SESSION['stuff']);
	echo 'ok';
?>

PHP:

//button with onclick command
if(checkLevel('3')){?><td class="navTopTab_0"><a onClick="clearCase();" href="inputClaim.php">INPUT CLAIM</a></td><?php };

PHP: