MediaWiki extensions manual
Release status: stable
Implementation User interface
Author(s) alex4401 (Alex44019talk)
Latest version 1.0.0
MediaWiki v0.4+: MediaWiki 1.39+
v0.1 - v0.3: MediaWiki 1.37+
Database changes No
License GNU General Public License 3.0 or later
Example ARK: Survival Evolved Wiki
Temtem Wiki

The ThemeToggle extension that allows for themes with minimal flash of wrongly styled content. This is achieved by delivering the script responsible for theme loading earlier and separately from other scripts (bypassing the requirement on MediaWiki's ResourceLoader client and having to wait for other modules such as TabberNeue, skin scripts, and so on).


  • Download and place the file(s) in a directory called ThemeToggle in your extensions/ folder.
  • Add the following code at the bottom of your LocalSettings.php file:
    wfLoadExtension( 'ThemeToggle' );
  • If running a wiki farm or a network and themes are to be shared, adjust $wgThemeToggleLoadScriptOverride and $wgThemeTogglePreferenceGroup appropriately.
  • On aggressively cached setups, you might want to wait (until you're done trying the extension out) with toggling $wgThemeToggleEnableForAnonymousUsers on and having the HTML cache purged.
  •   Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.

Wikis on wiki.gg have this extension enabled by default. You can prepare the theme CSS and definitions before the deployment is done.




Controls which theme switcher module is used. If auto, uses simple when there's two or less themes, and dropdown otherwise.
Accepted values: auto, simple, dropdown, custom.
Default: auto
Controls whether the extension will be enabled for anonymous visitors.
Changing this requires the HTML cache (Cloudflare level) to be purged for your wiki, as the
Default: true
Overrides the suffix used for server-side user's theme preference ID. The suffix exists because wiki.gg shares user preferences between all the wikis in the whole network, and so it is used to avoid poisoning the preference values for other wikis, and causing issues.
If null, the wiki ID is used - on wiki.gg it consists of the wiki and the language, for example ark_en.
Changing this setting to a single, unique value allows for sharing the preference between your English wiki and its translations. It's recommended that you simply chop off the language code from the wiki ID: for ARK: Survival Evolved Wiki this would be ark. However, all of those wikis should have their theme definitions and styles kept in sync (while there is currently no definition sharing implemented, the $wgThemeToggleLoadScriptOverride variable can be used to share the CSS).
Warning: Previous theme preferences are not migrated when the value is changed, and registered users will lose their theme choices. Old entries are also not removed from the database.
Default: null
Overrides the ResourceLoader endpoint that will be used to load theme styles from. This may be used to share theme styles between multiple wikis by choosing a single one as the "authority" - which will act as the sole style provider.
If null, defaults to the wiki's own load.php path.
Default: null
Example: to have the theme CSS loaded from your English wiki, set to /load.php on all translations.

Defining themes


Themes can be defined at MediaWiki:Theme-definitions, with format resembling the Gadgets extension.

Each line is a new theme definition, and must begin with an asterisk (*), followed by an internal theme ID (which must be a single alphanumerical word / not contain any characters other than letters or numbers), and optionally options inside square brackets. For example:

* light[bundled]
* dark


* blue[bundled|default]
* red[bundled]
* purple

The square brackets can be omitted if empty.

Names to be displayed in the theme switcher, or Special:Preferences, can be set by creating a system message titled MediaWiki:Theme-ID.

Definitions are bundled with the JavaScript sent to the browser. You may need to refresh your browser's cache before changes to the definitions list (or theme CSS) become visible.


Option Description
bundled Indicates the theme CSS is already included within MediaWiki:Vector.css (or another skin's) or MediaWiki:Common.css, and no extra needs to be loaded.

The default theme of choice should have this option set.
default Indicates this theme should be enabled by default for new users. If multiple themes have this flag set, only the first one matters. If no theme has this flag set, the first defined is assumed.

If there is a light and a dark theme defined and there is no theme with this flag set, the script will try to detect the user's preference automatically.

Theme CSS


Themes without the bundled flag have their CSS loaded from a system message titled MediaWiki:Theme-ID.css (for example MediaWiki:Theme-dark.css).

Monitoring theme usage


Special:ThemeUsage shows the number of registered users with each theme set as their preferred.

Users with preferences that are no longer valid (because the theme was removed from the definitions list) are shown in a separate row.



Please submit translations via the project's Weblate panel (log in with Discord).

See also