function executeXhr(url) {
  // branch for native XMLHttpRequest object
  if (window.XMLHttpRequest) {
    req = new XMLHttpRequest();
    req.onreadystatechange = processAjaxResponse;
    req.open("GET", url, true);
    req.send(null);
  } // branch for IE/Windows ActiveX version
  else if (window.ActiveXObject) {
    req = new ActiveXObject("Microsoft.XMLHTTP");
    if (req) {
      req.onreadystatechange = processAjaxResponse;
      req.open("GET", url, true);
      req.send();
    }
  }
}

function processAjaxResponse() {
  // only if req shows "loaded"
  if (req.readyState == 4)
  {
    // only if "OK"
    if (req.status == 200) {
      var contentDiv = document.getElementById('contentDetails');
      contentDiv.innerHTML = req.responseText;
    } else {
//      alert("There was a problem retrieving the XML data:\n" + req.statusText);
    }
  }
}