Gadget kitchen/en

Welcome to the gadget kitchen. This is a tutorial for how you can write and use gadgets and user-scripts in JavaScript.

What are user scripts and gadgets?
MediaWiki allows anyone to write public JavaScript code to immediately change the behavior of the software. This code can be shared with other users. This code is located in wiki pages.


 * A user script can be edited by the original author (if it is stored in the  namespace) and by anyone with the "edituserjs" user-right (usually just interface administrators). The code is usually hosted on a sub page of your user page. Examples include: XTools/ArticleInfo.js and m:User:Hoo man/useful links.js. User scripts are similar to the personal JavaScript pages such as Special:MyPage/common.js, but they allow single code chunks to be shared with other users.
 * A gadget is a user script which has been "promoted" by an interface administrator, by adding it to MediaWiki:Gadgets-definition. Logged-in users can enable gadgets in the "Gadgets" tab of their user preferences. Gadgets are created and managed by interface administrators.
 * For completeness: There is also the siteJS located at MediaWiki:Common.js. The JavaScript in that file affects everyone and is executed automatically for both logged-out and logged-in users. Interface administrators can edit that page.

If you're running your own copy of MediaWiki, needs to be enabled for user scripts to work, and the  extension needs to be installed to make it possible to promote individual scripts to gadget status. For a nicer development experience, ensure that the extension is installed on your wiki.

Write your first user script
In this section, you create an example user script which calculates the estimated reading time of a wiki page.
 * 1) Ensure you are logged in.
 * 2) Visit Special:MyPage/common.js. This page holds your personal JavaScript that is loaded on every page view (except for Special:Preferences).
 * 3) Either create the page or edit the page if it already exists.
 * 4) Copy the following six lines and paste these lines into the page:
 * 5) Click "Publish changes".
 * 6) Go to any page. Look at the title.
 * 1) Go to any page. Look at the title.

This example user script is taken from. There are more examples for simple user scripts on that page.

In general, check out the JavaScript coding conventions to write JavaScript that complies with MediaWiki's style.

Developing user scripts and gadgets
This section lists resources which are either needed or helpful for non-simple user scripts.

ResourceLoader
Since 2015 (MediaWiki 1.26), gadgets must use ResourceLoader (T107399). is a core feature of MediaWiki that intelligently delivers JavaScript and CSS assets to users and readers. Because Gadgets are coded in JavaScript, as a Gadget coder you're bound to interact with ResourceLoader.

Your gadget should load useful ResourceLoader modules.


 * Modules — A list of JavaScript libraries, jQuery plugins and MediaWiki utilities that already exist within ResourceLoader for you to reuse.
 * See the jQuery documentation for information about using jQuery in MediaWiki
 * Developing with ResourceLoader — A list of useful practices, like enabling the debug mode and help with debugging.
 * Also see the ResourceLoader best practices.

OOUI
OOUI is a JavaScript library with user interface elements (for example pop-up windows) specifically for use in MediaWiki. The library can be used in gadgets.

MediaWiki Action API
See Special:MyLanguage/API for more information.

VisualEditor
See VisualEditor/Gadgets for a tutorial specifically for VisualEditor gadgets.

Debugging user scripts and gadgets

 * Gadgets are usually compacted by the ResourceLoader, minimized and aggregated. Use the  URI parameter (preceded by   or , of course), to ask for the non-compacted version of the page and to load the "original source form" of your gadget. Also see Developing with ResourceLoader for more information.
 * Learn how to use the Developer Tools of your browser (for example how to disable the cache in your browser). See the corresponding documentation: Chrome/Chromium, Firefox, Internet Explorer, Opera, Safari.
 * If an existing gadget has problems, you can also use the page Special:Gadgets to find the source code location of a gadget.

Privacy and external content
You should not load external resources that may harm users privacy. In Wikimedia wikis, the following domains are considered safe:
 * *.wiktionary.org
 * *.wikimedia.org
 * *.wikibooks.org
 * *.wikisource.org
 * *.wikiversity.org
 * *.wikinews.org
 * *.wikiquote.org
 * *.wikidata.org
 * *.wikivoyage.org
 * www.mediawiki.org

A more complex user script example
Check out MediaWiki:Tutorial-QuickRC.js which uses mw.loader, mw.util, mw.html, mw.user from ResourceLoader, the MediaWiki Action API, a jQuery UI dialog, jQuery AJAX, and jQuery event binding.

Copy and paste the contents of MediaWiki:Tutorial-QuickRC.js into your Special:MyPage/common.js.

The result should be the same as above, but now you can modify the script, play with it, and replace it with something else entirely.

Load an existing user script
In the previous section, you copied the content of a user script. In this section, you will load the existing script MediaWiki:Tutorial-QuickRC.js instead.
 * 1) Ensure you are logged in.
 * 2) Visit Special:MyPage/common.js. This page holds your personal JavaScript that is loaded on every page view (except for Special:Preferences).
 * 3) Either create the page or edit the page if it already exists.
 * 4) Copy the following text and paste it into the page: mw.loader.load('//www.mediawiki.org/w/index.php?title=MediaWiki:Tutorial-QuickRC.js&action=raw&ctype=text/javascript');
 * 5) Click "Publish changes". You should now have a link in the "Tools" section called "Quick changelog".
 * 6) Click "Quick changelog". You get a pop-up window. It shows you a subset of the recent changes on this website.

Use a script on another Wikimedia wiki
If you want to use a script on another Wikimedia website (for example English Wikipedia instead of MediaWiki.org), you perform the same steps as above: you tell ResourceLoader to load your code. Visit your common.js on English Wikipedia, and add the following: mw.loader.load("//www.mediawiki.org/w/index.php?title=MediaWiki:Tutorial-QuickRC.js&action=raw&ctype=text/javascript");

You can also load the user script which you just created above, by changing  in the previous line to   (replace   and   accordingly). This first requires that you do not store the code of your user script in Special:MyPage/common.js itself but instead in a separate sub page of your user page.

This also helps to keep code in one single place, so you have to update code in only one place.

Disadvantages and problems of gadgets

 * Gadgets are developed by community members. As of today, there is no formal code review required for gadgets on Wikimedia sites (see T71445). Please follow the best practices listed on this page.
 * On Wikimedia sites, the process how to "promote" a user script to a gadget in the "Gadgets" tab of the user preferences is not always clear. You will have to find an interface administrator and might have to provide deployment instructions to them.
 * Wikimedia lacks a systematic process for re-using, modifying and contributing to existing user scripts and gadgets.

Ideas what to work on
If you want to write features that directly help Wikimedia community members, see:


 * Gadget Kitchen/Requests in general, however that page does not look be popular so you might waste time.
 * w:Wikipedia:User scripts/Requests for English Wikipedia

Deploying or enabling a gadget
If your user script should become a gadget (see the definitions above) on a wiki, the following steps are needed:


 * Steps for the user script author:
 * Recruit an experienced developer to review your gadget code. There is no formal process to do so.
 * Check with community members if there aren't any concerns with enabling the gadget on a wiki. For the website MediaWiki.org itself, this would be Project:Current_issues.
 * Recruit a site administrator with interface rights. See the page Special:ListUsers/interface-admin on your wiki.
 * Steps for the interface administrator:
 * Copy your JS & CSS files in the  namespace on your wiki, and make sure the page names have the prefix  . Example:
 * Define the gadget on the MediaWiki:Gadgets-definition page of your wiki. That includes the modules used, dependencies, JS, and CSS file names, etc. This will allow users to enable the gadget on the Special:Preferences page of your wiki. Example:
 * Create a page for the gadget in the  namespace with prefix  . This will generate a label for the gadget on the Special:Preferences page of your wiki. Example:

Related pages

 * Wikipedia:User scripts on the English Wikipedia and its alternatives in other languages are the primary hubs for user script and gadget development in Wikipedia.
 * The user scripts guide on the English Wikipedia has tons of useful information to get you started.
 * Wikipedia:Gadget page on English Wikipedia
 * Slides for a workshop to teach the basics of user scripts and gadgets (part of Small wiki toolkits)
 * List of gadgets by popularity across all Wikimedia projects
 * For a specific website, see Special:GadgetUsage for the number of users that each gadget has
 * Compatibility - MediaWiki's JavaScript support per browser and browser version
 * A video tutorial from the year 2012 regarding gadgets and user scripts. This is a bit outdated and the quality could be better, but shows how to use developer tools etc.
 * See Extension:EventLogging for a mechanism to gather data created from users interacting with a gadget.