<!DOCTYPE html><html lang="en">
<head> <meta charset="UTF-8">
<title>Title</title>
</head><body> <span class="timespan"></span>
<script src="libs/jquery-1.11.3.js"></script>
<script> var starttime = new Date("2017/11/20");
setInterval(function () {
var nowtime = new Date();
var time = starttime - nowtime;
var day = parseInt(time / 1000 / 60 / 60 / 24);
var hour = parseInt(time / 1000 / 60 / 60 % 24);
var minute = parseInt(time / 1000 / 60 % 60);
var seconds = parseInt(time / 1000 % 60);
$('.timespan').html(day + "天" + hour + "小时" + minute + "分钟" + seconds + "秒");
}, 1000);
</script></body>
</html>