$(document).ready(function(){
    var i = 1;
    window.setInterval(function() {         
        var numNodes = $('#nieuwsholder ul li').length;

        if (i < numNodes) {
            $('#nieuwsholder ul').animate(
                {'top': -i*20 }, "normal"
            )
            i++;
        } else {
            $('#nieuwsholder ul').animate(
                {'top': 0 }, "normal"
            )
            i = 1;          
        }
    }, 4000);
});