title: How to get atomic clock with JavaScript?
body: <p>I want to create JavaScript countdown, but I have to use atomic clock (non local PC time).
  I find the <a href="http://worldclockapi.com/api/json/est/now" rel="nofollow noreferrer">http://worldclockapi.com/api/json/est/now</a>, which gets you a JSON.</p>
  
  <p>There is a property <strong>currentFileTime</strong> (timestamp), but not UNIX timestamp.</p>
  
  <p>How to convert this timestamp to UNIX timestamp, get the Date Object and check Date, Hours, Minutes and Seconds?</p>
  
  <p>Thanks</p>