Tabbing between separate radio groups with the same name

When tabbing and the next element is an enabled <input type="radio" name="group-id">:

if the radio is checked then it gets focused
if no other radio input with the same group-id is already checked then it gets focused (if another radio with the same group-id is checked then the the radio is ignored and the focus moves to the next tabbable element)

This works as expected, however when there are multiple groups with the same name under different <form> elements, they should be considered as separate groups.

The case:

<form>
  <input type="radio" name="groupA" value="a" ></input>
  <input type="radio" name="groupA" value="b" checked></input>
</form>          
<form>
  <button><!-- focused button --></button>
  <input type="radio" name="groupA" value="c" ></input>
  <input type="radio" name="groupA" value="d" ></input>
</form>

Currently tabbing from the button in the second form will move the focus to <input value="b"> instead of the expected focus of <input value="c">.

This is inherited caveat from Tabbable.

idoros / zeejs

Tabbing between separate radio groups with the same name #19