var currentimage = 0;

function ShowStartImage()
{
   var theUrl;
   theUrl = imageURL + imagelist[0];
   document.mainimage.src = theUrl;
}

function ShowNextImage()
{
    if (document.images) {
		var theUrl;
		if (imagelist.length == 0) {
			theUrl = " ";
		} else {
			currentimage = (++currentimage) % imagelist.length
			theUrl = imageURL + imagelist[currentimage];
		}
		document.mainimage.src = theUrl;
    }
}