javascript timeout - example

<!DOCTYPE html>
<html>
<head>
<title> http://stackoverflow.com/questions/11439499/how-to-call-a-javascript-function-every-second-in-html/ </title>
<script type="text/javascript">
<!--
function CountdownAnzeigen(countdown){
    document.getElementById('countdown').innerHTML = countdown--;
    if (countdown>0) {
       window.setTimeout(function(){window.CountdownAnzeigen(countdown);}, 1000);
    } else { alert('The End');}
}
//-->
</script>
</head>
<body>
<input type="button" value="count down" onclick="window.CountdownAnzeigen(10)"/>
<div id="countdown"></div>
</body>
</html>