JSFiddle - React, Tailwind, and code Playground

HTML

<form action="">
    <input type="radio" id="focusID1" name="sex" value="male" /> Male<br />
    <input type="radio" id="focusID2" name="sex" value="female" /> Female<br />
</form>

CSS

.focused {
    width: 30px;
    height: 30px;
}

JavaScript

var elem = document.getElementById("focusID2");
if (elem != null) {
   elem.setAttribute("class", "focused");
   elem.focus();
}