var ajax = null;
if (window.XMLHttpRequest)
      ajax = new XMLHttpRequest();
else if (window.ActiveXObject)
      ajax = new ActiveXObject("Microsoft.XMLHTTP");
 
function refresh_div(Div, Seite)
{
      ajax.open("GET", Seite, true);
      ajax.onreadystatechange = function()
      {
            if(ajax.readyState == 4)
                  document.getElementById(Div).innerHTML = ajax.responseText;
      }
      ajax.send(null);
}