ами може с jquery
ето ти пример:
<html>
<head>
<script type="text/javascript" src="js/jquery.js"></script> - библиотеката на jqery
<script type="text/javascript">
$(document).ready(function() {
$("#showclick").hide();
setTimeout('addDot()',3000);
});
function addDot() {
$('#showclick').fadeIn("slow");
}
</script>
<style type="text/css">
#showclick { position: fixed; z-index: 9999; margin: 0 auto; bottom: 0px; width: 100%; text-align: center; background: #3333ff; color: white; padding: 20px; left: 0;}
</style>
</head>
<body>
<div id="showclick">hello world</div>
</body>
</html>