function actives() {
    var alleLinks = document.getElementById('menu').getElementsByTagName('a');
        var pagina;
        einde = window.location.href.indexOf('.aspx') + 5;
        pagina = window.location.href.substring(0,einde);
        
        
        for (var i = 0; i < alleLinks.length; i++) {
            if (pagina == alleLinks[i].href) { alleLinks[i].className = 'active'; }
        }
        
        alleLinks = document.getElementById('linksMenu').getElementsByTagName('a');
        for (var i = 0; i < alleLinks.length; i++) {
            if (pagina == alleLinks[i].href) {  alleLinks[i].className = 'active'; }
        }
}

if (window.attachEvent) { window.attachEvent('onload', actives) }
else { window.addEventListener('load', actives, false) }