UNIX epoch time in Javascript

Reference:

  1. http://stackoverflow.com/questions/4631928/convert-utc-epoch-to-local-date-with-javascript
  2. http://stackoverflow.com/questions/9456138/how-can-i-get-seconds-since-epoch-in-javascript
  3. http://www.experts123.com/q/what-is-unix-epoch-time.html
  4. https://zh-tw.flightaware.com/commercial/flightxml/faq.rvt