13位，毫秒时间戳接口：

淘宝

http://api.m.taobao.com/rest/api3.do?api=mtop.common.getTimestamp

http://acs.m.taobao.com/gw/mtop.common.getTimestamp/

京东

https://sgm-m.jd.com/h5/

<https://api.m.jd.com/api?appid=paimai&functionId=getPaimaiRealTimeData&body={%22paimaiId%22:276304054}>

苏宁

http://quan.suning.com/getSysTime.do

华为

https://buy.vmall.com/getSkuRushbuyInfo.json

美团

https://cube.meituan.com/ipromotion/cube/toc/component/base/getServerCurrentTime

本地获取：

JavaScript

<script>document.write((new Date()).getTime()); </script>