Version 0.9.0 of package Firefox-Javascript-Repl has just been released in GNU ELPA. You can now find it in M-x list-packages RET.
Firefox-Javascript-Repl describes itself as: ================= Jack into Firefox ================= More at https://elpa.gnu.org/packages/firefox-javascript-repl.html ## Summary: Usage: Start the REPL: M-x firefox-javascript-repl RET To stop the REPL, kill the *firefox-javascript-debugger* buffer: C-x k RET yes RET or quit Firefox from within Firefox. Description: REPL into a new Firefox instance's JavaScript engine. A new throwaway Firefox profile directory is created before each run, so you won't need to modify your existing profiles. This mode takes care of starting the new Firefox process in debugging mode, which may be tedious to do by hand. This `comint' mode is barebones and unstructured, meant for quick JavaScript experiments. On newer versions of Emacs with `comint-indirect-buffer' support, syntax highlighting happens on the current statement. Paste each statement from `example.js' into the REPL to try it out. ## Recent NEWS: [Not available 🙁]