https://www.thetwistedgroove.com/wp-content/themes/piano-black/js/scroll.js

1jQuery.easing.quart = function (x, t, b, c, d) {
2	return -c * ((t=t/d-1)*t*t*t - 1) + b;
3};
4
5jQuery(document).ready(function(){
6
7	jQuery('a[href*=#wrapper],a[href*=#respond]').click(function() {
8		if (location.pathname.replace(/^\//,'') == this.pathname.replace(/^\//,'') && location.hostname == this.hostname) {
9			var $target = jQuery(this.hash);
10			$target = $target.length && $target || jQuery('[name=' + this.hash.slice(1) +']');
11			if ($target.length) {
12				var targetOffset = $target.offset().top;
13				jQuery('html,body').animate({ scrollTop: targetOffset }, 1200, 'quart');
14				return false;
15			}
16		}
17	});
18
19});