hjkl автор John McCrary

You will be able to navigate left, down, up, and right using the "hjkl" keys respectively. New in version 1.1 - configure any keys for navigation: WASD and others now available.

Configuration screenshot

All other vim extensions modify too many existing keyboard shortcuts for my taste. This is an incredibly minimal extension that I developed for my own productivity. It may not work on every webpage.

See the full source code at https://github.com/jomccr/firefox-hjkl/