:focus selector filter?

:focus selector filter?


Since querySelectorAll has native support for :focus to find the
focused element, does it make sense to add support for the older
browsers? I can tell you that this is a common request on #jquery.
$.expr[':'].focus = function(a){ return (a ==
document.activeElement); }
This works in ie6+, ff3+, chrome2+, saf4+, opera9+, both with and
without qSA.
So the question is: is adding this worth the non-compatibility with
FF2, Chrome1, and Safari 3? Something that can be resolved through
proper documentation, perhaps.
Also, AFAICT, only the elements that support tabindex work with this
filter:
A, AREA, BUTTON, INPUT, OBJECT, SELECT, and TEXTAREA.