https://www.ednet.ns.ca/sites/all/modules/back_to_top/js/back_to_top.js?tlvh12

1(function ($) {
2	Drupal.behaviors.backtotop = {
3		attach: function(context) {
4			var exist= jQuery('#backtotop').length;
5      if(exist == 0) {
6        $("body", context).once(function() {
7          $(this).append("<button id='backtotop'>"+Drupal.t(Drupal.settings.back_to_top.back_to_top_button_text)+"</button>");
8        });
9      }
10			$(window).scroll(function() {
11				if($(this).scrollTop() > Drupal.settings.back_to_top.back_to_top_button_trigger) {
12					$('#backtotop').fadeIn();
13				} else {
14					$('#backtotop').stop(true).fadeOut();
15				}
16			});
17
18      $('#backtotop', context).once(function() {
19			  $(this).click(function() {
20			    $("html, body").bind("scroll mousedown DOMMouseScroll mousewheel keyup", function() {
21            $('html, body').stop();
22          });
23          $('html,body').animate({ scrollTop: 0 }, 1200, 'easeOutQuart', function() {
24            $("html, body").unbind("scroll mousedown DOMMouseScroll mousewheel keyup");
25          });
26          return false;
27			  });
28			});
29		}
30	};
31})(jQuery);