Yes
Greasemonkey is a Mozilla Firefox extension that allows users to install
scripts that make on-the-fly changes to web page content after or before the
page is loaded in the browser (also known as augmented browsing).
https://en.wikipedia.org/wiki/Greasemonkey
Greasemonkey is available in the Abrowser (along with some scripts)
https://trisquel.info/en/browser/addons?keys=greasemonkey&tid=All
Once Greasemonkey installed you download scripts such as Viewtube or from
http://www.userscripts.org
Greasemonkey is available in Qupzilla via > Preferences > Extensions
In Midori via > Preferences > Extensions > User Scripts
