var objLeftad = document.getElementById("leftad");
objLeftad.style.visibility = "hidden";

var idLeftad = setInterval("fadeLeftad()", 3000);

function fadeLeftad() {
	clearInterval(idLeftad);

	if (objLeftad && objLeftad.style && objLeftad.style.filter) {
		objLeftad.filters[0].apply();
		objLeftad.style.visibility = "visible";
		objLeftad.filters[0].play();
	}
	else
		objLeftad.style.visibility = "visible";

	idLeftad = setInterval("fadeLeftad(false)", 20000);
}