var timerID = null;
var timerRunning = false;

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

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

function showtime(){
	var timenow = new Date();
	var time_h, time_m, time_s, fulltime, timetmp;
	timetmp=timenow.getHours().toString();
	if (timetmp.length==1) {
		time_h='0' + timetmp;
	} else {
		time_h=timetmp;
	}
	timetmp=timenow.getMinutes().toString();
	if (timetmp.length==1) {
		time_m='0' + timetmp;
	} else {
		time_m=timetmp;
	}
	timetmp=timenow.getSeconds().toString();
	if (timetmp.length==1) {
		time_s='0' + timetmp;
	} else {
		time_s=timetmp;
	}
	fulltime=time_h+":"+time_m+":"+time_s;

	clocktime.value = fulltime ;
	timerID = setTimeout("showtime()",1000);
	timerRunning = true;
}