We basically don't implement the "tooLong" validity state thing at all. There's a TODO comment in the code pointing to bug 613016 and bug 613019. The latter seems like a prerequisite for the behavior this bug is asking for.
(In reply to Boris Zbarsky [:bz] from comment #1) > We basically don't implement the "tooLong" validity state thing at all. Well, you do implement it insofar as the property exists (with a constant value of `false`) rather than being `undefined`, which makes trying to feature-detect proper support for `.tooLong` more trouble than it's worth. > The latter [bug 613019] seems like a prerequisite for the behavior this bug is asking for. Agreed.
This bug should be fixed now that bug 613019 just landed.
Indeed. Test passes in current Nightly.
Do we have tests for this?
Yes, a test for this was added as part of bug 613019. See https://hg.mozilla.org/mozilla-central/file/e2bb8f329f10/dom/html/test/test_bug613019.html