[destus]

<script>

    document.onscroll = function (event) {
        var scrollTop = window.pageYOffset || document.documentElement.scrollTop;
        console.log(scrollTop);
        if(scrollTop > 200) {
            var el = document.getElementById('main-navbar');
            el.id = 'main-navbar2';
        }
else{
var el = document.getElementById('main-navbar2');
el.id = 'main-navbar';
}

    }

</script>