SO http://is.gd/JvjIp6

HTML

<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<div class="scroll-down">Please scroll down for more content</div>

JavaScript

(function ($) {
  $(document).ready(function(){
 
	$(function () {
		$(window).scroll(function () {
            // set distance user needs to scroll before we hide message
			if ($(this).scrollTop() < 300) {
				$('.scroll-down').fadeIn();
			} else {
				$('.scroll-down').fadeOut();
			}
		});

	
	});

});
  }(jQuery));