JSFiddle - React, Tailwind, and code Playground

HTML

Header:
<br />
<select id="myddl" name="myddl">
    <option value="1">One</option>
    <option value="2">Twooo</option>
    <option value="3">Three</option>
</select>
<div class="detail">
    <p>Detail</p>
        <br />
    <select id="Select5" name="myddl">
        <option value="1">One</option>
        <option value="2">Twooo</option>
        <option value="3">Three</option>
    </select>  </div>

JavaScript

$("#myddl").change(function()
{ 
    alert(myddl.val()); //$(this).
     $('.detail').find('select').val($(this).val());
});