function zonkartaPopup() {
    if (!document.getElementById) return false;
    if (!document.getElementsByTagName) return false;
    if (!document.getElementById("zonkarta_popup")) return false;

    var zonkartaPopup = document.getElementById("zonkarta_popup");

    zonkartaPopup.onclick = function() {
    window.open("img/other/zonkarta.jpg", "Zonkarta", "menubar=0,resizable=0,width=771,height=778");
    }
}