JSFiddle - React, Tailwind, and code Playground

HTML

<select id = "foo">
   <option value = "example">This example</option>
   <option value = "example2">This example Again</option>
   <option value = "bar">This is just a bar</option>
</select>

JavaScript

var selected = document.querySelector( '#foo > option[value="bar"]' );

alert(selected.index);