function createXMLHttpRequest() {

var ua;

if(window.XMLHttpRequest) {
    try {
      ua = new XMLHttpRequest();
    } catch(e) {
      ua = false;
    }
  } else if(window.ActiveXObject) {
    try {
      ua = new ActiveXObject("Microsoft.XMLHTTP");
    } catch(e) {
      ua = false;
    }
  }
  return ua;
}

var req = createXMLHttpRequest();

function sendRequest(pfad,ziel) {
 
  req.open('GET', pfad);   
  req.onreadystatechange = function() {handleResponse(ziel);};
  req.send(null);
}

function handleResponse(ziel) {

  if(req.readyState == 4){
    document.getElementById(ziel).innerHTML = req.responseText;
  }
  else
    document.getElementById(ziel).innerHTML = '<img style="margin:auto" src="includes/ajax/ajax-loader.gif" />';
}