Quoting Robin Williams .... "Well I feel sheepish."

I was sure those methods were case insensitive, and wrote them that way, and at least one is, getElementsByTagName, which is probably how it got into my head.
But ClassName is case sensitive.
Just a couple lines to fix, and sorry you had to invest so much time to find it.
Ugh!
I also had it wrong as I thought it was a disjunction, it is a conjunction.
It helps to read, and reread, the documentation I guess.
I tested with jsrt, acid3, and nasa, all still stand.
Also with your example, which works now.

Here's a funny thing about nasa, one of my earlier commits causes more of the site to appear, that is, you don't have to type showall any more to get all of the links.
That's one of those fixes here has lateral benefits there.

Here's something not so funny.
At least one of those Elements methods returns a live array.
You see this now and then, a live array, edbrowse doesn't implement a live array, and I wouldn't even know how to do it!
Some day we might have to deal with this.
I'm actually surprised it isn't tested anywhere in acid3.
I'm giving you this heads up, so you can watch for it while testing.
I've never seen code in the wild use the properties of a live array, I wouldn't if I were writing js, it's an unpredictable pain in the ass!
Ugh!

Karl Dahlke