var type;

function processReqChange() {
	if (req.readyState == 4) {			//reaches 4 when finished

		if (req.status == 200) {		//request went ok

			var xmlDoc = req.responseXML;

			if( type == 'poppics' ) {
				popPicsAction( xmlDoc );
			}

		} else {
				alert("There was a problem retrieving the XML data:\n" + req.statusText);
		}
	}
}