function getXMLHttp() {
	var xmlHttp;
	try {
		// Firefox, Opera 8.0+, Safari
		xmlHttp = new XMLHttpRequest();
	} catch (e) {
		// Internet Explorer
		try {
			xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e) {
				alert("Your browser does not support AJAX!");
				return false;
			}
		}
	}
	return xmlHttp;
}

function AJAXInteraction(url, callback) {

   	var req = init();
    req.onreadystatechange = processRequest;

    function init() {
   		if (window.XMLHttpRequest) {
        	return new XMLHttpRequest();
        } else if (window.ActiveXObject) {
        	return new ActiveXObject("Microsoft.XMLHTTP");
        }
    }

    function processRequest () {
      // readyState of 4 signifies request is complete
      if (req.readyState == 4) {
		// status of 200 signifies sucessful HTTP call
        if (req.status == 200) {
          if (callback) callback(req.responseXML);
        }
      }
    }

    this.doGet = function() {
      // make a HTTP GET request to the URL asynchronously
      req.open("GET", url, true);
      req.send(null);
   	}
}