<!DOCTYPE html>
<html>
<head>
<style>
span { color: red }
:checked + span { color: green }
input { display: none }
</style>

<body onload='document.getElementById("foo").setAttribute("type", "checkbox");
              document.getElementById("bar").setAttribute("type", "radio")'>
<input checked="checked" id="foo"><span>There should be no red</span>
<input checked="checked" id="bar"><span>There should be no red</span>
</body>
</html>