addLoadEvent(function() {
    document.getElementById('button_tijden').onclick = function() {
        document.getElementById('tarieven_html').style.display = 'none';
        if (document.getElementById('tijden_html').style.display == 'block') {
            document.getElementById('tijden_html').style.display = 'none'
        } else {
            document.getElementById('tijden_html').style.display = 'block'
        }
    };
    document.getElementById('button_tarieven').onclick = function() {
        document.getElementById('tijden_html').style.display = 'none';
        if (document.getElementById('tarieven_html').style.display == 'block') {
            document.getElementById('tarieven_html').style.display = 'none'
        } else {
            document.getElementById('tarieven_html').style.display = 'block'
        }
    };
});