function createAjaxObject() {
	var ro;
	var browser = navigator.appName;
	if (browser == "Microsoft Internet Explorer") {
		ro = new ActiveXObject("Microsoft.XMLHTTP");
	}
	else {
		ro = new XMLHttpRequest();
	}
	return ro;
}

function getDeliveryCost() {

	function doAjaxRequest(url) {	
		// setup the ajax object, define the response handler and send the data
		http = createAjaxObject();
		http.open('GET', url);
		http.onreadystatechange = handleResponse;
		http.send(null);
	}
	
	function handleResponse() {
		if (http.readyState == 4) {
			var response = http.responseText;
			document.getElementById('delivery_cost').innerHTML = response;
		}
	}
		
	if (document.getElementById('postcode')) {
	
		// convert to upper
		//document.getElementById('postcode').value.toUpperCase();
		
		// get the postcode value
		var postcode = document.getElementById('postcode').value;
		
		if (postcode.length == 0) {
			alert('Please enter your full delivery postcode.');
			document.getElementById('postcode').focus();
			return false;
		}
		
		// get the course id
		// build the GET URL to the PHP file
		var url = getWebRoot() + 'inc/get_delivery_cost.php?postcode=' + escape(postcode);
		doAjaxRequest(url);
	}
}