JSFiddle - React, Tailwind, and code Playground

HTML

<input type="radio" name="myoptions" value="blue" class="required"> Blue<br />
<input type="radio" name="myoptions" value="red"> Red<br />
<input type="radio" name="myoptions" value="green"> Green
<br><br>
<span>Submit</span>

JavaScript

$("span").click(function() {
    if ($("[name=myoptions]:checked").size() ==0) {
            alert("Select an option");
    }

});