I wonder if there is any (noticeable) performance improvement when removing code comments from .php, .js, .css, .html, and similar files?Answer1:
It depends how many comments there are.
In general though, most developers have a live version of all their code that is compressed- no whitespace outside of text formatting, no comments, etc. And an offline version that is developer-friendly with all the extra formatting and so on.
Another thing to note is with '//' style comments, they won't really hinder performance since the parser skips straight to the next line. With /**/ comments, the parsers has to keep reading all your comments until it encounters the closing */ so its <em>ever-so-slightly</em> more cpu intensive.
Paragraph 2 though, imo. :)