function calcage(secs, num1, num2) {
  s = ((Math.floor(secs/num1))%num2).toString();
  return s;
}

function CountBack(secs) {
  if (secs < 0) {
    document.getElementById("odpocet").innerHTML = "Už je konec";
    return;
  }
  dnu = Math.floor(secs / 86400);
  DisplayStr = "Zbýv";
  if(dnu == 1) {
	DisplayStr += "á už jen <b>1 den, ";
  } else if(dnu >= 2 && dnu <= 4) {
	DisplayStr += "ají už jen <b>" + dnu + " dny, ";
  } else if(dnu >= 5) {
	DisplayStr += "á už jen <b>" + dnu + " dnů, ";
  } else {
	DisplayStr += "á <b>";
  }
  DisplayStr += calcage(secs,3600,24) + " hodin a " + calcage(secs,60,60) + " minut.</b>"
  
  document.getElementById("odpocet").innerHTML = DisplayStr;
  setTimeout("CountBack(" + (secs - 60) + ")", 60000);
}

var dthen = new Date("05/23/2009 0:00 AM");
var dnow = new Date();
ddiff = new Date(dthen-dnow);
gsecs = Math.floor(ddiff.valueOf()/1000);