var target_url = "";
var mlsID = null;

function retrieveUrl(url, mls) {

	mlsID = mls;
	target_url = url+'&mls='+mlsID;

	if(request == null){ try{ createRequest(); } catch(err) { sendMessage(err);} }
	if(request) {
		try{
			request.open('GET', target_url, true);
			request.onreadystatechange = openMarker;
			request.send('');
		} catch(err){
			alert(err);
		}
	}
}

function openMarker() {

	if (request.readyState == 4 && request.responseXML) {

		var xmlDocument = request.responseXML;
    	var xml_message = xmlDocument.getElementsByTagName('results').item(0).firstChild.data;
    	if(xml_message!=""){ getMlsInfo(mlsID); }
	}
}