intl-tel-input/examples/partials/initPromise.html

A JavaScript plugin for entering and validating international telephone numbers

<!-- polyfill for IE11 -->
<script src="https://cdn.jsdelivr.net/npm/es6-promise@4/dist/es6-promise.auto.js"></script> 

<p>
  Status:
  <span id="status">Initialising...</span>
</p>
<input id="phone" type="tel">