https://manatipua.org/user/themes/agency/js/cbpAnimatedHeader.js

1/**
2 * cbpAnimatedHeader.js v1.0.0
3 * http://www.codrops.com
4 *
5 * Licensed under the MIT license.
6 * http://www.opensource.org/licenses/mit-license.php
7 * 
8 * Copyright 2013, Codrops
9 * http://www.codrops.com
10 */
11var cbpAnimatedHeader = (function() {
12
13	var docElem = document.documentElement,
14		header = document.querySelector( '.navbar-fixed-top' ),
15		didScroll = false,
16		changeHeaderOn = 300;
17
18	function init() {
19		window.addEventListener( 'scroll', function( event ) {
20			if( !didScroll ) {
21				didScroll = true;
22				setTimeout( scrollPage, 250 );
23			}
24		}, false );
25	}
26
27	function scrollPage() {
28		var sy = scrollY();
29		if ( sy >= changeHeaderOn ) {
30			classie.add( header, 'navbar-shrink' );
31		}
32		else {
33			classie.remove( header, 'navbar-shrink' );
34		}
35		didScroll = false;
36	}
37
38	function scrollY() {
39		return window.pageYOffset || docElem.scrollTop;
40	}
41
42	init();
43
44})();