Using “label for” on radio buttons

Question

When using the \"label for\" parameter on radio buttons, to be 508 compliant*, is the following correct?

Answer 1

Either structure is valid and accessible, but the for attribute should be equal to the id of the input element:

button text

or

button text

The for attribute is optional in the second version (label containing input), but IIRC there were some older browsers that didn't make the label text clickable unless you included it. The first version (label after input) is easier to style with CSS using the adjacent sibling selector +:

input[type="radio"]:checked+label {font-weight:bold;}