I'm confused. The HTML on a page should be automatically copyrighted to the author already. It's absolutely an expression of creative work just like a book, or software, or music.
That being said, it doesn't follow that it would make it illegal for any technology or any consumer to alter a website page appearance. You are free to modify copyrighted works as long as you don't distribute that work.
That being said, it doesn't follow that it would make it illegal for any technology or any consumer to alter a website page appearance. You are free to modify copyrighted works as long as you don't distribute that work.