jQuery倒计时代码(超简单)

<!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>