I've thought about this before but ended up letting us add a couple constants. I think we *should* only be accessing these in places where we know we're in a browser environment (since we're checking `nodeType`), but I wasn't sure at the time so didn't press the matter. Since then though we've added the constants in a couple other places and so long as it's supported in all browsers, we should probably just use `Node.*`. If anybody knows for sure or wants to test all browsers to make sure, chime up :)