<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<h1 id="a"></h1>
</body>
<script type="text/javascript">
var dateLOa=new Date();
var dateLOa1=new Date('2017/5/1');
var dateLOa2=dateLOa1-dateLOa;
var dateLOa3=dateLOa2/1000;
var dateLOa4=parseInt(dateLOa3/(60*60*24));
document.getElementById('a').innerHTML='距离2017年5月1号还有'+dateLOa4+'天';
</script>
</html>