[Matre]

<span id='timer'>60</span>
<input type='button' onclick='start(); this.onclick = new Function;' value='начать отсчёт' />
<script type='text/javascript'>
	function start() {
		var t = document.getElementById("timer");
		setTimeout(function () {
			if (--t.innerHTML == 0)
				t.innerHTML = "Time is out!";
			else
				setTimeout(arguments.callee, 1000);
		}, 1000);
	}
</script>