function hodiny()
{
 dnes=new Date();

with (dnes)
{ hodin=getHours(); minut=getMinutes(); sekund=getSeconds(); }

cas =(hodin<10 ? "0" : "" )+hodin;
cas+=(minut<10 ? ":0" : ":" )+minut;
cas+=(sekund<10 ? ":0" : ":" )+sekund;

document.all.cifernik.innerText=cas;
window.setTimeout("hodiny();",1000);
}