Skip to content
userChromeJS / autoconfig.js and extensions
Branch: master
Clone or download
Type Name Latest commit message Commit time
Failed to load latest commit information.
chrome Add files via upload Mar 26, 2019
extensions Add files via upload Mar 26, 2019
installation-folder Create config-prefs.js Nov 29, 2017
screenshots Add files via upload Nov 29, 2017
LICENSE Update Feb 18, 2019


Tested on Firefox Developer Edition 66.0b8, Windows 10


  1. Just for Firefox Developer Edition (main compatibility target), Firefox Nightly and Firefox ESR. It will not work on Firefox release/stable or Firefox Beta.

  2. Save config.js to Firefox installation folder (usually C:\Program Files (x86)\Mozilla Firefox), next to firefox.exe.

  3. Save config-prefs.js into \defaults\pref inside Firefox installation folder (usually C:\Program Files (x86)\Mozilla Firefox\defaults\pref), next to channel-prefs.js.

  4. Click Firefox menu button (☰) -> Help -> Troubleshooting information (or simply open the address "about:support"), then click Open folder. This is the folder of your Firefox profile. In there, create a new folder called chrome.

  5. Inside chrome, create another new folder called utils, then save all these files into it.

  6. Save rebuild_userChrome.uc.js into chrome.

  7. Save the desired userChromeJS scripts into chrome. Read below the description of each one.

  8. Restart Firefox.

userChromeJS scripts

(click on each to expand)

Adjust URLBar Popup Position and Width In Fx 48, URLBar Popup was stretched to fill the entire width of the browser. This script restores the previous behavior, with the popup inheriting the width and position of URLBar.

Note: there are similar userChrome.css alternatives, but the URLBar width can change depending on the buttons around and depending on the size of the window. You can't set dynamic width with pure CSS, so JS is needed.

Download link.

Firefox default:

With this script:

Master Password+ Locks Firefox with password. It will prompt the password on browser startup or anytime when you lock it with Ctrl+Alt+Shift+W.

You need to set a master password in Firefox Options > Privacy & Security > [×] Use a master password.

Download link.




userChromeJS Manager (the blue ones are restartless)

Status Bar, Extension Options Menu, MinMaxClose Button, newDownloadPlus.uc.js and legacy extensions:

You can’t perform that action at this time.