function switch_navi_childs(nav_object,nav_name) {
    nav_object.href='#';
    var childs = document.getElementById('navi_childs_'+nav_name);
    if (childs) {
        if (childs.style.display == 'none') {
            childs.style.display = 'block';
        }
        else {
            childs.style.display = 'none';
        }
    }
}