var src = [];
var duration = 8;
var ads = []; 
var ct = 0;

function switchAd() {
	var n=(ct+1)%src.length;
	if (ads[n] && (ads[n].complete || ads[n].complete==null)) {
		document["ad_image"].src = ads[ct=n].src;
	}
	ads[n=(ct+1)%src.length] = new Image;
	ads[n].src = src[n];
	setTimeout("switchAd()",duration*1000);
}

function processReqChange()
{
 if (req.readyState == 4 && req.status == 200 && req.responseXML != null)
  {
    //alert( req.responseText );
	var img = document.getElementById('ad_image');
	
	var nl = req.responseXML.getElementsByTagName('slide');
	for (var i = 0; i < nl.length; i++) 
	{
		var nli = nl.item( i );
		var imgsrc = nli.getAttribute('src').toString();
		src[i] = imgsrc;
	}
	switchAd();
  }
}

function loadXMLDoc( url )
{
  req = false;
  if(window.XMLHttpRequest) {
    try {
      req = new XMLHttpRequest();
        } catch(e) {
      req = false;
        }
  }
  else if(window.ActiveXObject)
  {
    try {
      req = new ActiveXObject("Msxml2.XMLHTTP");
    } catch(e) {
    try {
      req = new ActiveXObject("Microsoft.XMLHTTP");
    } catch(e) {
      req = false;
    }
  }
  }
  if(req) {
    req.onreadystatechange = processReqChange;
    req.open("GET", url, true);
    req.send("");
  }
}