https://www.reliablecounter.com/cameras/js/scrolling-nav.js

1//jQuery to collapse the navbar on scroll
2$(window).scroll(function() {
3    if ($(".navbar").offset().top > 50) {
4        $(".navbar-fixed-top").addClass("top-nav-collapse");
5    } else {
6        $(".navbar-fixed-top").removeClass("top-nav-collapse");
7    }
8});
9
10//jQuery for page scrolling feature - requires jQuery Easing plugin
11$(function() {
12    $('a.page-scroll').bind('click', function(event) {
13        var $anchor = $(this);
14        $('html, body').stop().animate({
15            scrollTop: $($anchor.attr('href')).offset().top
16        }, 1500, 'easeInOutExpo');
17        event.preventDefault();
18    });
19});