

Tridactyl aims to re-implement Vimperator's feature in a way that is compatible with Firefox >= 57.0 Like Vimperator, it is incompatible with Firefox Quantum. It has also been designed to be very customisable and makes it easy to write powerful scripts. Additional web-specific features such as 'Hint' mode (which allows users to refer to links by labels or numbers), command line interface and key bindings to navigate back and forward links make it easy to navigate without touching the mouse. The project is a fork of Vimperator and like it, its appearance and user interface should be familiar to Vim users. Pentadactyl is an open source add-on for Firefox, designed to make browsing more efficient and more keyboard accessible. Note that this extension isn't compatible with Firefox >= 57.0 (see here for a discussion and alternatives)

It also allows the user to call up an external editor, e.g., GVim to edit text fields in web forms. It is a feature-rich add-on for Firefox and in addition to vi-like key bindings for moving around a web page, it has features such as a full ex-mode command line, tab completion, and a JavaScript shell. Vimperator is an open source extension for Mozilla Firefox inspired by the Vim text editor.
