function moveAD() {
    var nextTime = 600;
	var scrollTop = parseInt(document.body.scrollTop) + 35;
	var adTop = parseInt(ad.style.top);
	if (scrollTop != adTop) {
		var offsetSize = Math.ceil(Math.abs(adTop - scrollTop) / 25);
		offsetSize = (adTop > scrollTop) ? offsetSize : -offsetSize;
		ad.style.top = adTop - offsetSize;
		nextTime = 12;
	}
	setTimeout("moveAD()", nextTime);
}

var ad;

function showAD(adID) {
	if (document.getElementById) {
		ad = document.getElementById(adID);
		ad.style.visibility = "visible";
		ad.style.top = document.body.scrollTop;
		moveAD();
	}
}