Use the server time at the client side.
Include the sync.js into your html, and setup the timeURL to the time server.
<script>
var timeURL = "http://time.server.com/";
(function(w,s){
var f = d.getElementsByTagName(s)[0],
j = d.createElement(s),
j.async = true;
j.src = '/sync.js';
f.parentNode.insertBefore(j,f);
})(window,document,'script');
</script>The time server is a very lightweight server, capable of handling thousands of requests per second, and returns a json with time.
The script sync.js will override Date class, and it will contain the server time; to use the client time you must use LocalDate class.
The time synchronization is asynchronous and the first time could take a few seconds, but we store the offset in localStorage to avoid resynchronizing for the next hour.
<script>
var timeURL = "http://37.153.159.15:9999";
var timeSynced = false;
var retry = setInterval(function() {
if (timeSynced) {
clearInterval(retry);
alert("Time is sinced, there is " + (Date.now() - LocalDate.now()) + "ms of difference");
}
}, 100);
</script>
<script src="sync.js"></script>The server is very simple, it is written in NodeJS. I'll push a C server which performs much better.
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