function _newXMLHttpRequest() {
  var http_request;
  if(window.XMLHttpRequest) { // native XMLHttpRequest object (FireFox, etc.)
    try {
      http_request = new XMLHttpRequest();
    } catch(e) {
      throw ("Failed to create (native) XMLHttpRequest");
    }
  } else if(window.ActiveXObject) { //IE
    try {
        http_request = new ActiveXObject("Msxml2.XMLHTTP");
    } catch(e) {
      try {
        http_request = new ActiveXObject("Microsoft.XMLHTTP");
      } catch(e) {
        throw ("Failed to create (ActiveX) XMLHttpRequest object");
      }
    }
  }
  return http_request;
}

function loadHeader(id) {
  var request = _newXMLHttpRequest();
  request.open('GET', "com_html/h.html", false);
  request.send(null);
  var div = document.getElementById(id);
  div.innerHTML = request.responseText;
}

  function loadFooter(id) {
  var request = _newXMLHttpRequest();
  request.open('GET', "com_html/f.html", false);
  request.send(null);
  var div = document.getElementById(id);
  div.innerHTML = request.responseText;
}