<!DOCTYPE html>
<html>
<body>
Radio Button: <input type="radio" id="myRadio">
<button onclick="disable()">Disable radio button</button>
<button onclick="undisable()">Undisable radio button</button>
<script>
function disable() {
document.getElementById("myRadio").disabled = true;
}
function undisable() {
document.getElementById("myRadio").disabled = false;
}
</script>
</body>
</html>