window.onload = function() {
    toggleBox('box1', false);
    toggleBox('box2', false);
    toggleBox('boxs3', false);
}

function toggleBox(eId, boxVisible) {
    var item = $(eId);
    if (boxVisible) {
        Element.show(item);
    } else {
        Element.hide(item);
    }
}

function menuShow(eId) {
   $(eId).style.visibility = 'visible';
}
function menuHide(eId) {
   $(eId).style.visibility = 'hidden';
}

function checkConference(workshopId) {
    if ($(workshopId).checked)
        switch (workshopId) {
            case 'workshop_1':
                if (!$('conference_1').checked) {
                    $('conference_1').checked = true;
                }
                break;
            case 'workshop_2':
                if (!$('conference_3').checked) {
                    $('conference_3').checked = true;
                }
                break;
            case 'workshop_3':
                if (!$('conference_4').checked) {
                    $('conference_4').checked = true;
                }
                break;
        }
}
function checkWorkshop(conferenceId) {
    if (!$(conferenceId).checked)
        switch (conferenceId) {
            case 'conference_1':
                if ($('workshop_1').checked) {
                    $('workshop_1').checked = false;
                }
                break;
            case 'conference_3':
                if ($('workshop_2').checked) {
                    $('workshop_2').checked = false;
                }
                break;
            case 'conference_4':
                if ($('workshop_3').checked) {
                    $('workshop_3').checked = false;
                }
                break;
        }
}