var curAgenda;

function fnShowAgenda(toonagenda) {
    var obj = document.getElementById('div_' + toonagenda + 'Agenda');
    
    if (curAgenda == null) {
        curAgenda = document.getElementById('div_concertAgenda');
    } 

    curAgenda.style.display = "none";
    obj.style.display = "block";
    curAgenda = obj;
}