<!--
    function blocking(nr) {
        if (document.layers) {
            current = (document.layers[nr].display == 'none') ? 'block' : 'none';
            document.layers[nr].display = current;
        } else if (document.all) {
            current = (document.all[nr].style.display == 'none') ? 'block' : 'none';
            document.all[nr].style.display = current;
        } else if (document.getElementById) {
            vista = (document.getElementById(nr).style.display == 'none') ? 'block' : 'none';
            document.getElementById(nr).style.display = vista;
        }
    }
//-->