CODE EXAMPLE FOR JAVASCRIPT

jquery phone number mask

<script type='text/javascript' src="https://cdnjs.cloudflare.com/ajax/libs/jquery.inputmask/5.0.5/jquery.inputmask.min.js"></script>
<script>
  $(function () {
    $('#contact_phone').inputmask({"mask": "(999) 999-9999"})
  });
</script>