var xmlHttp;

function GetXmlHttpObject() {
  var xmlHttp=null;
  try {
    // Firefox, Opera 8.0+, Safari
    xmlHttp=new XMLHttpRequest();
  } catch (e) {
    // Internet Explorer
    try {
      xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
  }
  return xmlHttp;
}

function ajaxReplace(url,replacediv,waitobj) {
  if (waitobj) { waitobj.style.visibility='visible'; }
  xmlHttp=GetXmlHttpObject();
  if (xmlHttp==null) {
    alert ("Your browser does not support AJAX!");
    return;
  }
  xmlHttp.onreadystatechange=function() {
    if (xmlHttp.readyState==4) {
      replacediv.innerHTML=xmlHttp.responseText;
      if (waitobj) { waitobj.style.visibility='hidden'; }
    }
  }
  xmlHttp.open("GET",url,true);
  xmlHttp.send(null);
}