Here's a nginx config and SSI page to do the same
https://gist.github.com/1678779
even supports json and jsonp
41 karma · joined October 23, 2011
even supports json and jsonp
Also, both the client and server software is open-source, so that can be confirmed too.
Also, a mobile phones time is synchronized by the GSM network, it doesn't drift much (if at all).