https://impecca.com/skin/frontend/rwd/lamby-darkblue/js/totop.js

1/*--------| UItoTop jQuery Plugin 1.1-------------------*/
2(function($){
3	$.fn.UItoTop = function(options) {
4
5 		var defaults = {
6			text: '',
7			min: 200,
8			inDelay:600,
9			outDelay:400,
10  			containerID: 'toTop',
11			containerHoverID: 'toTopHover',
12			scrollSpeed: 1200,
13			easingType: 'linear'
14 		};
15
16 		var settings = $.extend(defaults, options);
17		var containerIDhash = '#' + settings.containerID;
18		var containerHoverIDHash = '#'+settings.containerHoverID;
19		
20		$('body').append('<a href="#" id="'+settings.containerID+'">'+settings.text+'</a>');
21		$(containerIDhash).hide().click(function(){
22			$('html, body').animate({scrollTop:0}, settings.scrollSpeed, settings.easingType);
23			$('#'+settings.containerHoverID, this).stop().animate({'opacity': 0 }, settings.inDelay, settings.easingType);
24			return false;
25		})
26		.prepend('<span id="'+settings.containerHoverID+'"></span>')
27		.hover(function() {
28				$(containerHoverIDHash, this).stop().animate({
29					'opacity': 1
30				}, 600, 'linear');
31			}, function() { 
32				$(containerHoverIDHash, this).stop().animate({
33					'opacity': 0
34				}, 700, 'linear');
35			});
36					
37		$(window).scroll(function() {
38			var sd = $(window).scrollTop();
39			if(typeof document.body.style.maxHeight === "undefined") {
40				$(containerIDhash).css({
41					'position': 'absolute',
42					'top': $(window).scrollTop() + $(window).height() - 50
43				});
44			}
45			if ( sd > settings.min ) 
46				$(containerIDhash).fadeIn(settings.inDelay);
47			else 
48				$(containerIDhash).fadeOut(settings.Outdelay);
49		});
50
51};
52})(jQuery);
53jQuery(window).load(function() {
54  jQuery().UItoTop();
55	});
56
57/*--------| End UItoTop -------------------*/
58