JS节日倒计时效果

<script type="text/javascript">
var urodz= new Date("August 9,2018"); 
var s = "2008北京奥运会"; 
var now = new Date(); 
var ile = urodz.getTime() - now.getTime(); 
var dni = Math.floor(ile / (1000 * 60 * 60 * 24)); 

if (dni > 1) 
document.write("今天离"+s+"还有"+dni +"天") 
else if (dni == 1) 
document.write("只有2天啦！") 
else if (dni == 0) 
document.write("只有1天啦！") 
else 
document.write("期待奥运会再次来到中国！");
</script>