<!DOCTYPE html>
<html>
<head>
<style>
div { color:blue; }
p { color:green; }
span { color:red; display:none; }
</style>
<script src="http://code.jquery.com/jquery-latest.js"></script>
</head>
<body>
<div id="mydiv" style="position: fixed; font-size: 100px;">Try scrolling the iframe.</div>
<p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p><p>Paragraph</p>
<script>
$(window).scroll(function () {
$("#mydiv").css("display", "none").fadeIn("slow");
});
</script>
</body>
</html>