https://northernsunrise.net/repository/designs/parts/scripts/jquery.backTop.js

1(function ($) {
2	$.fn.backTop = function (options) {
3		var backBtn = this;
4
5		var settings = $.extend({
6			'position': 400,
7			'speed': 500,
8			'color': 'white'
9		}, options);
10
11		//Settings
12		var position = settings['position'];
13		var speed = settings['speed'];
14		var color = settings['color'];
15
16		backBtn.css({
17			'right': 20,
18			'bottom': 20,
19			'position': 'fixed',
20		});
21
22		$(document).scroll(function () {
23			var pos = $(window).scrollTop();
24
25			if (pos >= position) {
26				backBtn.fadeIn(speed);
27			} else {
28				backBtn.fadeOut(speed);
29			}
30		});
31
32		backBtn.click(function () {
33			$("html, body").animate({ scrollTop: 0 }, { duration: 1200 });
34			$("a").first().focus();
35		});
36	}
37
38}(jQuery));