That used to be possible by reading the styling in JS, but that was considered a privacy bug, since any website could slurp information from your browser histor

That used to be possible by reading the styling in JS, but that was considered a privacy bug, since any website could slurp information from your browser history. Therefore there was an overhaul of what kind of styling could be done based on history, and what could be read back about it in JS: https://blog.mozilla.org/security/2010/03/31/plugging-the-css-history-leak/ https://blog.mozilla.org/security/2010/03/31/plugging-the-cs...