I ran into this bug while testing jQuery 1.3b1:

$('input[name=foo', '#form');
=> Throws a context.getElementsByName is not a function error.

Turns out Sizzle will call

getElementsByName

even when there is a context argument passed to the selector, and this breaks when the context doesn't support

getElementsByName

. AFAIK this only works on

document

(i.e. no context).

I also found while fixing this bug that

input[name="foo"]

will NOT use the NAME selector (it falls back to the TAG-based selector).

I've a couple of patches to Sizzle that fixes these 2 bugs with tests over at my Github fork: http://github.com/chuyeow/sizzle/commits/context_selector_fixes (commits 19d4277 and be83e65).

I'll be generating a plain old patchfile as well in case that's more convenient :)