function zwin2(f){

var t = document.getElementById(f);

if(t.style.display=="none") {  t.style.display="block"; }
else {   t.style.display="none"; } 
}


function pokaz(b)
{

var bb = "d"+b;
var cb = "na"+b;
document.getElementById("d0").style.display="none";
document.getElementById("d1").style.display="none";
document.getElementById("d2").style.display="none";
document.getElementById("d3").style.display="none";
document.getElementById(bb).style.display="block";

document.getElementById("na0").className="";
document.getElementById("na1").className="";
document.getElementById("na2").className="";
document.getElementById("na3").className="";
document.getElementById(cb).className="aktiv";
}