According to the spec, I think it should be possible with the bolean
readonly attribute. Only it doesn't work with radio and checkboxes for some obscure reason.
Is it possible for you to programmatically give all inputs but the checked ones the
disabled attribute? That would prevent any changes. The downside is that the disabled values won't be sent when the form is submitted, but if this is only for display that shouldn't matter.
CODE
<input type="radio" name="fruit" disabled>Apple
<input type="radio" name="fruit" disabled>Pear
<input type="radio" name="fruit" checked>Banana
<input type="radio" name="fruit" disabled>Cherry
You could make all inputs disabled, but then the checked one will be grayed out, if that matters to you. It doesn't seem possible to change the color with CSS. It is for for example disabled text inputs, but it doesn't seem to work with radio buttons and checkboxes.