function hideAllSubsections(nb) {
        for (i = 1 ; i < nb ; i++) {
                document.getElementById('subsections-' + i).style.display = 'None';
        }
}

function showSubsections(id, nb_sections, nb_subsections) {
        display = document.getElementById(id).style.display                
        //hideAllSubsections(nb_sections);
        if (nb_subsections > 0 && display != '') { 
            document.getElementById(id).style.display = '';
        }else {
            document.getElementById(id).style.display = 'None';
        }
}