[Rise]

condpattern,

<script src="http://learn.javascript.ru/files/tutorial/browser/cookie/cookie.js"></script>
<script>
function clickTimer() {
	if (!d) {
		d = new Date().setHours(24, 0, 0, 0); 
		setCookie('timestamp', d, { expires: d, path: '/' });
		startTimer();
	}
}
function startTimer() {
	var a = d;
	var b = new Date();
	var c = a - b;
	if (a >= b) {
		var h = parseInt(c / 36e5) % 24;
		if (h < 10) h = '0' + h;
		var m = parseInt(c / 6e4) % 60;
		if (m < 10) m = '0' + m;
		var s = parseInt(c / 1e3) % 60;
		if (s < 10) s = '0' + s;
		e.innerHTML = h + ' : ' + m + ' : ' + s;
		setTimeout(startTimer, 1e3);
	} else {
		d = 0;
		deleteCookie('timestamp');
		e.innerHTML = 'Click Me';
	}
}
</script>

<div id="countdown">Click Me</div>

<script>
var d = getCookie('timestamp');
var e = document.getElementById('countdown');
	e.onclick = clickTimer;
if (d) startTimer();
</script>