JS 倒记时

<h2>本窗口将在<span id="sec"></span>秒后自动关闭退出！</h2>	

<script type="text/javascript">

var MAX_TIME_SEC = 5;
var curTime = MAX_TIME_SEC;
var showId = document.getElementById("sec");
showId.innerHTML=curTime ; 

var interval = setInterval(showTime,1000);

function showTime(){
	if(curTime > 0){
		showId.innerHTML=curTime ;
		curTime--;
	}else{
		clearInterval(interval);
		window.close();
	} 
}
</script>