导航显示向上滚动

Question

I copied this script from another website, and i'm not sure what i'm doing wrong here. The script is suppose to remove / add a class, but for some reason it is not working.

I tested it on this url, and here it is working perfectly http://rubenkoops.nl/script_library/cms/content/01-home/nav_hide_on_scroll_html_preview/

For some reason it is nog working on this url http://18493.hosts.ma-cloud.nl/

I got the feeling that i'm missing something really dumb, can anybody figure this out?

<style type="text/css">

    header {
        background: #f5b335;
        height: 40px;
        position: fixed;
        top: 0;
        left: 0;
        transition: top 0.2s ease-in-out;
        width: 100%;
    }

    .nav-up {
        top: -40px;
    }
  </style>

<script type='text/javascript'>//<![CDATA[
    $(function(){
    // Hide Header on on scroll down
    var didScroll;
    var lastScrollTop = 0;
    var delta = 5;
    var navbarHeight = $('header').outerHeight();

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

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

    function hasScrolled() {
        var st = $(this).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
            $('header').removeClass('nav-down').addClass('nav-up');
        } else {
            // Scroll Up
            if(st + $(window).height() < $(document).height()) {
                $('header').removeClass('nav-up').addClass('nav-down');
            }
        }

        lastScrollTop = st;
    }
    });//]]> 

</script>

<header class="nav-down">
    Dit is het menu
</header>

Answer 1

The problem is that the script expects a $("header") element AKA:

<header></header>

but you have

<div id="header"></div>

So you logically have two solutions.

1. Change the script to $("#header")
2. Or use the <header> Element