<html>
<script>
var countdown = function(timeout) {
var countUI = document.getElementById("count");
if(!!countUI) {
countUI.innerHTML = timeout;
if (timeout == 0) {
alert("end");
}
else {
timeout--;
setTimeout(function(){
countdown(timeout)
}, 1000);
}
}
}
function init(){
countdown(5);
}
</script>
<body onload=init();>
<div id="count">5</div>
</body>
</html>
