https://www.uniurb.it/it/portale/js/main.js

1jQuery(document).ready(function($){
2	// browser window scroll (in pixels) after which the "back to top" link is shown
3	var offset = 300,
4		//browser window scroll (in pixels) after which the "back to top" link opacity is reduced
5		offset_opacity = 1200,
6		//duration of the top scrolling animation (in ms)
7		scroll_top_duration = 700,
8		//grab the "back to top" link
9		$back_to_top = $('.cd-top');
10
11	//hide or show the "back to top" link
12	$(window).scroll(function(){
13		( $(this).scrollTop() > offset ) ? $back_to_top.addClass('cd-is-visible') : $back_to_top.removeClass('cd-is-visible cd-fade-out');
14		if( $(this).scrollTop() > offset_opacity ) { 
15			$back_to_top.addClass('cd-fade-out');
16		}
17	});
18
19	//smooth scroll to top
20	$back_to_top.on('click', function(event){
21		event.preventDefault();
22		$('body,html').animate({
23			scrollTop: 0 ,
24		 	}, scroll_top_duration
25		);
26	});
27
28});