JSFiddle - React, Tailwind, and code Playground

by zaurmag

HTML

<select class="a">
	<option value="a" selected>1</option>
	<option value="b">2</option>
	<option value="c">3</option>
	<option value="d">4</option>
	<option value="f">5</option>
</select>

<select class="b">
	<option value="a" selected>1</option>
	<option value="b">2</option>
	<option value="c">3</option>
	<option value="d">4</option>
	<option value="f">5</option>
</select>

JavaScript

document.querySelector('select.a').value = document.querySelector('select.a').querySelectorAll('option')[3].value;

document.querySelector('select.b').selectedIndex = 3;