JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.slim.js"></script>
<select name="woot" id="officeSelect" class="form-control phone-block__select" onchange="var phones = $('.phones .phone').hide(); phones.eq($(this).val()).toggle();">
	<option value="0">Краснодар</option><option value="1">Анапа</option><option value="2">Туапсе</option><option value="3">Абинск</option><option value="4">Слаянск-на-Кубани</option><option value="5">Армавир</option></select>

JavaScript

$('#officeSelect').val();