JSFiddle - React, Tailwind, and code Playground
by holden321
HTML
<div id="vopr">
<input name=v1 type="radio" onclick="vopr()">3
<br>
<input name=v1 type="radio" onclick="vopr(true)">4
<br>
<input name=v1 type="radio" onclick="vopr()">2
<hr>
</div>
<button id="next" disabled="disabled"
onclick="location.href='http://www.example.com'">ответить</button>
JavaScript
window.vopr=function(enable) {
document.getElementById("next").disabled=!enable;
}