[bes]

<script>
window.onload = function () {
	var timer = 8;
	function f() {
		alert(timer);
	}
	var int = setInterval (function () {
		document.body.innerHTML = timer;
		timer--; 
		if (timer == 0) {
			f();
			clearInterval(int);
		}
	}, 1000);
	
}
</script>