But what actually constitutes "modification of the AdSense code"?
The code I'm serving IS the AsSense code. All the .js script does is serve it up line by line. The code supplied to your browser is EXACTLY the same code that AdSense provides from their web page. Your browser can't tell the difference, though of course the HTML source code for the page doesn't contain the AsSense code, it contains a call to the .js file containing the AdSense code.
I would maintain that I'm not modifying the AdSense code, I'm just not serving it directly from an html file. The TOS don't say you have to serve it directly from an HTML file as far as I'm aware.
If course if the OFFICIAL Google position is that this is totally prohibited and if they find me doing it I'll be booted off the program, then I'll get to work making modifications, but as I said, I've been running it that way for the best part of a year, Google have looked at my site and pointed out one area where I wasn't quite in compliance with their TOS (which I corrected), but they never commented on the use of .js files containg the AdSense code. I don't have it on ALL my pages, but I'd guess maybe 1/2 of them.
Perhaps I need to send (anonymous) email to them to ask for an offical ruling. I'd rather do it anonymously just in case they hadn't noticed it and get upset about it!
As I said, I seem to be getting perfectly targeted ads which are closely related to the content of each page. If there's some technical reason why Google need the AsSense code in "plain language" in the HTML source, then I hope someone can explain that to me. Of course Google don't have to since "rules is rules", and I accept that. I'd just like to know since it's going to be quite a bit of work for me to modify several hundred pages!