JSFiddle - React, Tailwind, and code Playground

HTML

<select class="my">
    <option value="1">1</option>
    <option value="2">2</option>
    <option value="3">3</option>
    <option value="4">4</option>
</select>
<select class="menor">
    <option value="1">1</option>
    <option value="2">2</option>
    <option value="3">3</option>
    <option value="4">4</option>
</select>

CSS

.maior {
    background:red;
    height:60px;
}
select {
    width:60%;
}

JavaScript

$(".my").on('change', function () {
    var index = $(this).prop('selectedIndex');
    $(".menor").prop('selectedIndex', index);
});
$(document).ready(function () {

    $(".my").wrap("<div class='maior'></div>");
});