<div class="input">
<input type="text" name="name" required>
<span>Ваше имя</span>
</div>
<!-- -->
<div class="input">
<input type="text" name="phone" required>
<span>Номер телефона</span>
</div>
<div class="input">
<input type="text" name="phone" required>
<span>Ваш город</span>
<select name="form_select">
<option value="Nur-sultan" selected="selected">Нур-Султан</option>
<option value="Karaganda" >Караганда</option>
</select>
<select id="city" name="form_select" class="hidden" >
<option value="Nur-sultan" selected="selected">Нур-Султан</option>
<option value="Karaganda">Караганда</option>
</select>
.hidden {
display: none;
}
BX.ready(function() {
BX.bind(BX('city'), 'click', () => {
BX.removeClass(BX('city'), 'hidden');
});
});