Change nav items to active as you scroll

nav-scroll-active.js

$(window).scroll(function() {
    $('section').each(function(){
        var currentSection = $(this);
        var currentId = $(this).attr('id');
        
        if(currentSection.isOnScreen()){
            $('.sidenav a').removeClass('active');
            $('a[href="#'+currentId+'"]').addClass('active');
        }
    });
});