When is a JavaScript console no longer a JavaScript console? When it becomes the “Error” console. David Baron finally “fixed” Bug 154942 and added a CSS warning message to the console. Having a warning message is helpful. At least now developers will have a clue about what’s wrong. It still feels broken to have quirks mode happily handle “incorrect” MIME types and simply adding a valid doctype will break the page. For the sake of compatibility, I’d think Mozilla should handle some commonly broken, but reasonable, MIME types, such as text/plain. There’s more discussion about this confusing issue in Bug 113399.
I’m gonna miss the JavaScript console if it gets renamed. It has been a good helper for many years. I think I’d rather see a page compliance console like in iCab and keep the JavaScript separate.