var timerID = null;
var timerRunning = false;

function showtime()
{
  today = new Date();
  BigDay = new Date("May 21, 2010, 18:00");  // datum srazu
  
  timeLeft = (BigDay.getTime() - today.getTime());
  if ( timeLeft <= 0 )
  {
    Temp3='Sraz začal!';
    document.getElementById('timer').value=Temp3;
    stopClock();
    return;
  }
  
  msPerDay = 24 * 60 * 60 * 1000;
  e_daysLeft = timeLeft / msPerDay;
  daysLeft = Math.floor(e_daysLeft); 
  e_daysLeft = timeLeft / msPerDay;
  daysLeft = Math.floor(e_daysLeft);
  e_hrsLeft = (e_daysLeft - daysLeft)*24;
  hrsLeft = Math.floor(e_hrsLeft);
  minsLeft = Math.floor((e_hrsLeft - hrsLeft)*60);
  hrsLeft = hrsLeft;
  e_minsLeft = (e_hrsLeft - hrsLeft)*60;
  secLeft = Math.floor(e_hrsLeft);
  secLeft = Math.floor((e_minsLeft - minsLeft)*60);
  secLeft = secLeft;
  Temp3=''+daysLeft+'dní '+hrsLeft+'h : '+minsLeft+'min : '+secLeft+'s';
  document.getElementById('timer').value=Temp3;
  timerID = setTimeout("showtime()",1000);
  timerRunning = true;
}

var timerID = null;
var timerRunning = false;

function stopclock()
{ 
  if(timerRunning)
    clearTimeout(timerID);
  
  timerRunning = false;
} 

function stopClock()
{ 
    stopclock();
    return;
} 

function startclock()
{ 
  stopclock();
  showtime();
}