var tick;
function stopClock(){
	clearTimeout(tick);
}

function showClock(){
	var ut = new Date();
	var h,m,s;
	var time = "";
	h = ut.getHours();
	m = ut.getMinutes();
	s = ut.getSeconds();
	if (s<=9) s = "0"+s;
	if (m<=9) m = "0"+m;
	if (h<=9) h = "0"+h;
	time+= h+":"+m+":"+s;
	document.getElementById('clock').innerHTML = time;
	tick = setTimeout("showClock()",1000); 
}