GXMLHttp problem in IE8

Question

I have a function that uses GXMLHttp class to access data from server.

getGeoData: function() {

    var url = 'response.cfm';
    var request = GXmlHttp.create();
    request.open('GET', url, true);


    request.onreadystatechange = function() {

    if (request.readyState == 4) {
      console.info(request.responseXML);
      var xmlDoc = request.responseXML;
      var responseNode = xmlDoc.documentElement;
      //var type = responseNode.getAttribute("type");
      //var content = responseNode.firstChild.nodeValue;
      this_.dataArray = xmlDoc.getElementsByTagName("marker");
      this_.drawIcons();
     }
    }

    request.send(null);
    return false;
  }

It works fine in FF I mean it returns the contnts generated in response.cfm. But in IE8 the "request.responseXML" contains the whole contents of my Current page, not the response from Server.