Show/Hide Header

gistfile1.txt

// Handle show/hide of header
    // Technique borrowed from: https://medium.com/design-startups/hide-header-on-scroll-down-show-on-scroll-up-67bbaae9a78c
    // Hide Header on on scroll down
    var didScroll;
    var lastScrollTop = 0;
    var delta = 5;
    var navbarHeight = $('nav').outerHeight();

    $(window).scroll(function(event){
        didScroll = true;
    });

    setInterval(function() {
        if (didScroll) {
            hasScrolled();
            didScroll = false;
        }
    }, 250);

    function hasScrolled() {
        var st = $(window).scrollTop();
        
        // Make sure they scroll more than delta
        if(Math.abs(lastScrollTop - st) <= delta)
            return;
        
        // If they scrolled down and are past the navbar, add class .nav-up.
        // This is necessary so you never see what is "behind" the navbar.
        if (st > lastScrollTop && st > navbarHeight){
            // Scroll Down
            $('nav').removeClass('nav-down').addClass('nav-up');
        } else {
            // Scroll Up
            if(st + $(window).height() < $(document).height()) {
                $('nav').removeClass('nav-up').addClass('nav-down');
            }
        }
        
        lastScrollTop = st;
    }