function XmlHttpRequestWrapper() {
  var xmlhttp = false;
  if( window.XMLHttpRequest) {
    xmlhttp = new XMLHttpRequest();
  } else if(window.ActiveXObject) {
    try {
      xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    } catch(e) {
      xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
  }
  return xmlhttp;
}