html实时时间代码格式为年月日 时：分：秒

<!DOCTYPE html>
<html>
   <head>
      <title>实时时间</title>
      <meta charset="utf-8">
      <script>
         function updateTime() {
            var now = new Date();
            var year = now.getFullYear();
            var month = now.getMonth() + 1;
            var day = now.getDate();
            var hour = now.getHours();
            var minute = now.getMinutes();
            var second = now.getSeconds();
            var timeStr = year + '.' + month + '.' + day + ' ' + hour + ':' + minute + ':' + second;
            document.getElementById("time").innerHTML = timeStr;
         }
         setInterval(updateTime, 1000);
      </script>
   </head>
   <body>
      <h1>实时时间</h1>
      <div id="time"></div>
   </body>
</html>