Javascript+xml implements simple image rotation (only supports IE)

<script>
//Picture rotation
var a = 0 ;
var xmlDoc;
var image1 = ("image1");
function loadxml(path)
{
xmlDoc = new ActiveXObject("");
= false;
(path);
}
loadxml("");
function changeImage()
{
var ad = ("ad")[0];
if(a == )
{
a=0;
}
var path = [a].getAttribute("path");
var url = [a].text;
= path;
= function(){(url);};
a+=1;
setTimeout("changeImage()",1000);
}
changeImage();
</script>