https://www.melodicrock.it/wp-content/themes/melodirocknew/js/totop/jquery.ui.totop.js

1/*
2|--------------------------------------------------------------------------
3| UItoTop jQuery Plugin 1.2 by Matt Varone
4| http://www.mattvarone.com/web-design/uitotop-jquery-plugin/
5|--------------------------------------------------------------------------
6*/
7(function($){
8	$.fn.UItoTop = function(options) {
9
10 		var defaults = {
11    			text: 'To Top',
12    			min: 200,
13    			inDelay:600,
14    			outDelay:400,
15      			containerID: 'toTop',
16    			containerHoverID: 'toTopHover',
17    			scrollSpeed: 1200,
18    			easingType: 'linear'
19 		    },
20            settings = $.extend(defaults, options),
21            containerIDhash = '#' + settings.containerID,
22            containerHoverIDHash = '#'+settings.containerHoverID;
23		
24		$('body').append('<a href="#" id="'+settings.containerID+'">'+settings.text+'</a>');
25		$(containerIDhash).hide().on('click.UItoTop',function(){
26			$('html, body').animate({scrollTop:0}, settings.scrollSpeed, settings.easingType);
27			$('#'+settings.containerHoverID, this).stop().animate({'opacity': 0 }, settings.inDelay, settings.easingType);
28			return false;
29		})
30		.prepend('<span id="'+settings.containerHoverID+'"></span>')
31		.hover(function() {
32				$(containerHoverIDHash, this).stop().animate({
33					'opacity': 1
34				}, 600, 'linear');
35			}, function() { 
36				$(containerHoverIDHash, this).stop().animate({
37					'opacity': 0
38				}, 700, 'linear');
39			});
40					
41		$(window).scroll(function() {
42			var sd = $(window).scrollTop();
43			if(typeof document.body.style.maxHeight === "undefined") {
44				$(containerIDhash).css({
45					'position': 'absolute',
46					'top': sd + $(window).height() - 50
47				});
48			}
49			if ( sd > settings.min ) 
50				$(containerIDhash).fadeIn(settings.inDelay);
51			else 
52				$(containerIDhash).fadeOut(settings.Outdelay);
53		});
54};
55})(jQuery);