Most solutions I've seen to this require some kind of external daemon to be running that takes care of launching ytdl for you (since most web browsers don't allow extensions to run arbitrary commands.)
Firefox _does_ have support for running this daemon-like-thing for you using Native messaging[0] though.
youtube-dl-firefox-addon[1] seems to employ this, so perhaps give that one a try?
Firefox _does_ have support for running this daemon-like-thing for you using Native messaging[0] though.
youtube-dl-firefox-addon[1] seems to employ this, so perhaps give that one a try?
[0] https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...
[1] https://github.com/akhilkedia/youtube-dl-firefox-addon