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userChrome JS

When setting up FF Ultima, the Setup Wizard automatically handles userChromeJS setup as well. FF Ultima sources it's autoconfig setup from https://github.com/AlexVallat/firefox-scripts, with some modifications strictly to promote organization. The entire experience of integration was made to be very effortless for Users.

What does userChromeJS do in FF Ultima​

The main reason for userChromeJS integration is to serve as a bridge for userChrome Companion to function. The extension alone doesn't have the permission/ability to toggle moz-preferences, so instead we use bridge files:

To listen to the extensions broadcasted events and perform actions within the parent/child process when given the appropriate context. When viewing the files, you can grasp the entire process in about 2 minutes, theyre very minimal and self contained.

There's also a prefs.ffu.uc.js that serves as a "First Time - Preference Check" when the theme is installed for the first time.

Lastly, loader.ffu.uc.js. This script loads custom userchromejs scripts optimized for FF Ultima. More on that below.

Scripts​

If you're already familiar with userChromeJS/autoconfig, under the hood, FF Ultima's setup is no different than the usual "config-pref and config.js in the Firefox Install Directory". The biggest difference lies in what is in the chrome folder..

ucjs/autoconfig files are organized into chrome/userchromejs/. As usual with ucjs files, any *.uc.js script can be thrown into the chrome/userchromejs/scripts/ folder.

FF Ultima also includes custom scripts optimized just for the theme. These scripts are loaded seperately by loader.ffu.uc.js:

  • loader.ffu.uc.js loads any *.ffu.js script found in the chrome/userchromejs/scripts/ffu/ folder.
  • And *.ffu.js scripts feature the ability to be activated by mozilla preferences. This is done with a simple @pref line in the scripts' header.
  • *.ffu.js scripts are also optimized to create/destroy themselves based on their pref being turned on/off. Allowing for clean integration, and clean removal (on demand).
  • This also means *.ffu.js scripts are toggleable via userChrome Companion or the about:config page.

Like mentioned above, any uc.js script can be thrown into the scripts folder. But for the best experience, turn it into a ffu.js script by simply:

  • renaming it
  • giving it a @pref header
  • and putting it in the ffu/ folder instead.

Live Reload​

One of FF Ultimas custom scripts is a "userChrome Watcher" (ffu.chrome.watcher). When enabled, userChrome css and js files are monitored for changes and reloaded into the Browser. Meaning, restarting Firefox and clean Startup Cache restarts are no longer necessary when making your own changes to the files.

Additionally, there is a "userChrome Restarter" (ffu.clear.restart) that can be used to perform a clean Startup Cache Restart. It utilizes internal restart mechanism as if clicking the button on the about:support page.