I'm using this demo my project.
<http://tympanus.net/Development/ArticleIntroEffects/index3.html>

I want to do fixed menu after scrolling. And I use this js but it doesn't work.

```
    function fixDiv() {
        var $cache = $('#codrops-demos');
        if ($(window).scrollTop() > 100)
            $cache.css({'position': 'fixed', 'top': '10px', 'display': 'block'});
        else
            $cache.css({'position': 'relative', 'top': 'auto', 'display': 'none'});
    }
    $(window).scroll(fixDiv);
    fixDiv();

```

How can i make ?