// parts of this code were DL20081024 from
// http://codepunk.hardwar.org.uk/samp097.htm
// and parts DL20081024 from
// http://www.w3schools.com/XML/xml_http.asp
var position = 0;
var polling_interval = 8000;
var time_on_page = 0;
function startPolling(){setInterval("poll()",polling_interval)}

function poll(){
if (navigator.appName == "Microsoft Internet Explorer"){var position = document.body.scrollTop;}
else {var position = window.pageYOffset;}

var xmlhttp;
function loadXMLDoc(url)
{
xmlhttp=null;
if (window.XMLHttpRequest)
  {// code for all new browsers
  xmlhttp=new XMLHttpRequest();
  }
else if (window.ActiveXObject)
  {// code for IE5 and IE6
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
if (xmlhttp!=null)
  {
  xmlhttp.onreadystatechange=state_Change;
  xmlhttp.open("GET",url,true);
  xmlhttp.send(null);
  }
else
  {
  // browser does not support XMLHTTP
  }
}

function state_Change()
{
if (xmlhttp.readyState==4)
  {// 4 = "loaded"
  if (xmlhttp.status==200)
    {// 200 = OK
    // do nothing
    }
  else
    {
    // Problem retrieving XML data
    }
  }
}
time_on_page = time_on_page + (polling_interval / 1000);
// the following is a little safety function
// in order to set a timeout
if (time_on_page < 3600)
{
loadXMLDoc('bitlog/bit_for_position_polling.php?referer=timer_'+time_on_page+'_position_'+position);
}
return true;
}