JSFiddle - React, Tailwind, and code Playground
HTML
<script>
function test() {
if(document.getElementById('rdio2').checked==true) {
return true;
} else if(document.getElementById('rdio3').checked==true) {
return true;
} else if(document.getElementById('rdio4').checked==true) {
return true;
} else {
return confirm('are you sure?');
}
}
</script>
<form method="post" action="index.html" onSubmit="return test()">
<input type="radio" name="rdio" id="rdio2" value="b"/>
<input type="radio" name="rdio" id="rdio3" value="c"/>
<input type="radio" name="rdio" id="rdio4" value="d"/>
<input type="submit" value="Submit">
</form>