https://arigato.si/js/smoothscroll.js

1$(document).ready(function() {
2
3    // Click event for any anchor tag that's href starts with #
4    $('a[href^="#"]').click(function(event) {
5
6        // The id of the section we want to go to.
7        var id = $(this).attr("href");
8
9        // An offset to push the content down from the top.
10        var offset = 60;
11
12        // Our scroll target : the top position of the
13        // section that has the id referenced by our href.
14        var target = $(id).offset().top - offset;
15
16        // The magic...smooth scrollin' goodness.
17        $('html, body').animate({scrollTop:target}, 1000);
18
19        //prevent the page from jumping down to our section.
20        event.preventDefault();
21    });
22});
23
24jQuery(document).ready(function(){
25		var pxShow = 300;//height on which the button will show
26		var fadeInTime = 1000;//how slow/fast you want the button to show
27		var fadeOutTime = 1000;//how slow/fast you want the button to hide
28		var scrollSpeed = 1000;//how slow/fast you want the button to scroll to top. can be a value, 'slow', 'normal' or 'fast'
29		jQuery(window).scroll(function(){
30			if(jQuery(window).scrollTop() >= pxShow){
31				jQuery(".back-top").fadeIn(fadeInTime);
32			}else{
33				jQuery(".back-top").fadeOut(fadeOutTime);
34			}
35		});		 
36	});