//cross browser function to serialize an xmlDoc to a string of xml
function serializeXmlDoc(xmlDoc) {
  var text = false;
  try {
    // Gecko-based browsers, Safari, Opera.
    var serializer = new XMLSerializer();
    text = serializer.serializeToString(xmlDoc);
  }
  catch (e) {
    try {
      // Internet Explorer.
      text = xmlDoc.xml;
    }
    catch (e) {}
  }
  return text;
}