function compareAdd(itemId) {

	var url = 'http://www.psbspeakers.com/javascript/ajax_compareAdd.php?id=' +itemId;

	makeXmlRequest(url);
}

function makeXmlRequest(url) {
	var http_request = false;

	if (window.XMLHttpRequest) { // Mozilla, Safari, ...
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {
			http_request.overrideMimeType('text/xml');
		}
	} else if (window.ActiveXObject) { // IE
		try {
			http_request = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				http_request = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e) {}
		}
	}

	if (!http_request) {
		alert('Giving up :( Cannot create an XMLHTTP instance');
		return false;
	}
	http_request.onreadystatechange = function() { handleRequest(http_request); };
	http_request.open('GET', url, true);
	http_request.send(null);

}

function handleRequest(http_request) {

	if (http_request.readyState == 4) {
		if (http_request.status == 200) {
			//alert(http_request.responseText);
			document.getElementById('compareAdd').innerHTML = 'Added to product comparison';
			document.getElementById('compareAdd').href = 'javascript:void(0)';
			document.getElementById('compareAdd').className = 'compare_added';

		} 
		else {
			alert('There was a problem with the request.');
		}
	}
	else {

		//document.getElementById(ajaxElm).innerHTML = '<img src="img/ajax_loading.gif" alt="Loading..." />';
	}

}