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

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

function showtime()
{
	var now = new Date();
	var hours = now.getHours();
	var minutes = now.getMinutes();
	var seconds = now.getSeconds();
	var timeValue = "" + ((hours > 12) ? hours - 12 : hours);
	timeValue  += ((minutes < 10) ? ":0" : ":") + minutes;
	timeValue  += ((seconds < 10) ? ":0" : ":") + seconds;
	timeValue  += (hours >= 12) ? " P.M." : " A.M.";
	document.clock.face.value = timeValue;
	timerID = setTimeout("showtime()",1000);
	timerRunning = true;
}