Windows 7 (64 bit), Acrobat Pro 9.4(32 bit), FF 3.6.11(32 bit)
In Firefox, I briefly see the JS console flash and then vanish... but it stays empty.
IE will show the JS console if it's already open, and displays a brief error message and then crashes Acrobat: "Exception in line 18 of function top_level, script Page:Open". I don't have a function top_level. Acrobat isn't very good about telling you where an exception actually came from. This is NOT in a browser window thanks to 64-bit IE vs 32-bit Acrobat.
PS: I have JS debugging turned on and I set it to break on a throw... changing it to "trace" stopped the IE crash, so that's something... I even got the rest of the exception. Turns out my install of IE wants to download the PDF, and the submit is to a relative URL... it has to do with 32-bit Acrobat vs 64-bit IE. My hunting leads me to believe that there's no such thing as "64-bit Acrobat", and I haven't been able to convince my machine to install a 32-bit IE. Wheee.
I'm not at all sure when this broke. It could have been FF 3.6.11, or it could have been Acrobat 9.4. IIRC, it was working relatively recently... but then I haven't done much PDF JS debugging lately, so it could have been a version or two prior on either side.