function czas()
{
  var d = new Date();
  var h = d.getHours();
  var m = d.getMinutes();
  var s = d.getSeconds();

  m = pad(m);
  s = pad(s);

  document.getElementById('zegar').innerHTML = h+":"+m+":"+s;
  t = setTimeout('czas()', 500);
}

function pad(i)
{
  if(i<10){
    i="0"+i;
  }
  return i;
}