JSFiddle - React, Tailwind, and code Playground
HTML
<script src="//cdnjs.cloudflare.com/ajax/libs/moment.js/2.8.3/moment.min.js"></script>
<script src="http://momentjs.com/downloads/moment-timezone-with-data.min.js"></script>
<div id="myCoolNavBarr"></div>
CSS
//format each to just show the time and an abrv for the zone
var newYork = "<strong>NY</strong> " + newYork.format("h:mm: A");
var london = "<strong>LDN</strong> " + london.format("h:mm: A");
var hongKong = "<strong>HK</strong> " + hongKong.format("h:mm: A");
var tokyo = "<strong>TYO</strong> " + tokyo.format("h:mm: A");
JavaScript
//create a "moment"object from the current date/time
var rootDateTime = moment();
//clone that first instance and use the clone to create the next ones
//use the timezone functionality to display
var newYork = moment.tz("America/Los_Angeles").format("h:mm: A");
var london = moment.tz("Europe/London").format("h:mm: A");
var hongKong = moment.tz("Asia/Hong_Kong").format("h:mm: A");
var tokyo = moment.tz("Asia/Tokyo").format("h:mm: A");
//put them to use
$("#myCoolNavBarr").append("NY "+newYork+ " --- LDN " +london+ " --- HK " +hongKong+ " --- TYO " +tokyo)