JSFiddle - React, Tailwind, and code Playground

HTML

<select id='country' name = 'country'>  
    <option value='TW'>Taiwan</option>
    <option value='CN'>China</option>
    <option value='DE'>Germany</option>
    <option value='JP'>Japan</option>
    <option value='KR'>South Korea</option>
    <option value='US'>USA</option>
    <option>------------</option>
</select>

<select name='provinces' id='provinces'>
    <option>------------</option>";
</select>

JavaScript

$(document).ready(function() {
    $('#provinces').hide();

     $('#country').change(function () {
        if ($('#country option:selected').text() == "China"){
            $('#provinces').show();
        }
         else { 
              $('#provinces').hide();
         }
    });
});