JSFiddle - React, Tailwind, and code Playground

HTML

<form id="test">
<label><input type="radio" name="test" value="A"> A</label>
<label><input type="radio" name="test" value="B" checked> B</label>
<label><input type="radio" name="test" value="C"> C</label>
</form>

JavaScript

var form = document.getElementById("test");
alert(form.elements["test"].value);