JSFiddle - React, Tailwind, and code Playground

HTML

<select name="category_01" id="category_01">
<option value="0">--Select Category--</option>
<option value="7">Analysis technique</option>
<option value="6">Analyzed with</option>
<option value="1">CHEMICAL GROUP</option>
<option value="2">Compounds</option>
<option value="3">Detection Tech</option>
<option value="4">Injection Tech</option>
<option value="5">INSTUMENT</option>
<option value="8">Method</option>
</select>

JavaScript

$(document).ready(function(){
    alert($('#category_01').val());
});