Contact form add phone number (fake)

Script

<script>
var observer = new MutationObserver(function(mutations, obs) {
var $form = $('#formContact');
if ($form.length) {
obs.disconnect();
$form.css('visibility', 'hidden');
addPhoneField($form);
$form.css('visibility', 'visible');
}
});

observer.observe(document.body, { childList: true, subtree: true });

function addPhoneField($form) {
if ($form.find('.phone-field').length) return;

var phoneField = `
<div class="form-group phone-field">
<label for="contact_phone"><span class="required-asterisk">Telefon</span></label>
<input type="tel" id="contact_phone" class="form-control" placeholder="" required>
</div>
`;

$form.find('textarea[name="message"]').closest('div').before(phoneField);

$form.on('submit', function () {
var phone = $('#contact_phone').val().trim();
if (phone) {
var $msg = $form.find('textarea[name="message"]');
$msg.val('Telefon: ' + phone + '\n\n' + $msg.val());
}
});
}
</script>