To find text on the page using regular expressions in Mozilla Firefox

here's the addon for FF adds what You need
\r
https://addons.mozilla.org/en-US/firefox/addon/99836/

I understand that it is easier to ask, but most everything is easily searched)
Here https://addons.mozilla.org/ru/firefox/addon/2077/. Looked — works, and embedded in the search.

Have /Find Bar/, but not without glitches.

Thanks for the help