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This extension comes with MediaWiki 1.31 and above. Thus you do not have to download it again. However, you still need to follow the other instructions provided.
MediaWiki extensions manual
OOjs UI icon advanced.svg
Release status: stable
Implementation Tag , Parser function , Special page
Description Provides a dynamic view of the wiki's category structure as a tree.
Author(s) Daniel Kinzler (Duesentriebtalk)
Latest version continuous updates
Compatibility policy release branches
MediaWiki 1.25+
License GNU General Public License 2.0 or later
  • $wgCategoryTreeAllowTag
  • $wgCategoryTreeCategoryPageOptions
  • $wgCategoryTreePageCategoryOptions
  • $wgCategoryTreeSpecialPageOptions
  • $wgCategoryTreeMaxDepth
  • $wgCategoryTreeSidebarOptions
  • $wgCategoryTreeDefaultOptions
  • $wgCategoryTreeMaxChildren
  • $wgCategoryTreeCategoryPageMode
  • $wgCategoryTreeOmitNamespace
  • $wgCategoryTreeSidebarRoot
  • $wgCategoryTreeDisableCache
  • $wgCategoryTreeDefaultMode
  • $wgCategoryTreeForceHeaders
  • $wgCategoryTreeUseCategoryTable
  • $wgCategoryTreeHijackPageCategories
Translate the CategoryTree extension if it is available at translatewiki.net
Check usage and version matrix.
Issues Open tasks · Report a bug

The CategoryTree extension provides a dynamic view of the wiki's category structure as a tree. It uses AJAX to load parts of the tree on demand. CategoryTree was originally written by Daniel Kinzler as an external tool, but was later integrated into the MediaWiki software with the help of Tim Starling.


  • Download and place the file(s) in a directory called CategoryTree in your extensions/ folder.
  • Add the following code at the bottom of your LocalSettings.php:
    wfLoadExtension( 'CategoryTree' );
  • Yes Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.

To users running MediaWiki 1.27 or earlier:

The instructions above describe the new way of installing this extension using wfLoadExtension(). If you need to install this extension on these earlier versions (MediaWiki 1.27 and earlier), instead of wfLoadExtension( 'CategoryTree' );, you need to use:

require_once "$IP/extensions/CategoryTree/CategoryTree.php";


CategoryTree can be used in three ways:

  • directly on the category pages,
  • as a "custom tag" (or "parser function") to show a category structure in-line on a wiki page,
  • and as a special page.

The CategoryTree extension adds "expand" widgets to the subcategories listed on category pages.

The <categorytree> tag[edit]

Example. The result can be seen in the box below and on the right:

<categorytree mode="pages">Manual</categorytree>

The custom tag is called <categorytree>. For example, if you put <categorytree>Foo</categorytree> on a wiki page, it will show the contents of category Foo as a dynamic tree on that page (see example to the right). The tag accepts the following attributes, using a HTML-like syntax:

determines which pages are shown in the tree. This may be overridden by the use of the namespaces option. Possible values:
show subcategories only (configuration constant 0)
show subcategories and pages, except images (configuration constant 10), limited to 200 pages
show all pages, subcategories, images, etc. (configuration constant 20)
list parent categories instead of subcategories (configuration constant 100). This puts CategoryTree into "inverse" operation (supported since r36892, July 2008).
determines how many levels of the tree are shown initially. Default is 1. 0 means only the root node. The maximum value depends on the mode specified, and on the $wgCategoryTreeMaxDepth option. (Introduced between r20410 and r20840, Mar 30 2007; fully functional even with $wgCategoryTreeDynamicTag since r36864, July 2008.)
set this to "on" to only show the "root" node of the tree initially. Equivalent to depth="0". (Introduced in r20385, March 13 2007.) Deprecated as of r36864, July 2008: use depth="0" instead.
set this to "on" to hide the "root" node of the tree, i.e. hideroot=on. For example, it will not display the category name Foo.
determines when the namespace prefix should be hidden from entries in the tree (since r36864, July 2008). Possible values are:
always hide the prefix. Should be used only if all pages come from the same namespace (configuration constant 10).
never hide the namespace prefix, not even for categories (configuration constant 0).
hide the namespace of categories if only categories are shown, as with mode="categories" (configuration constant 30). This is equivalent to the old default behavior (before Jun 2008).
always hide the namespace of categories, but show all other prefixes (configuration constant 20). This is the new default behavior (since r36864, July 2008).
set this to "on" to show the number of entries in subcategories, i.e. showcount="on" (since r36864, July 2008). This is disabled per default for category trees inlined on pages, but enabled per default in category listings and on Special:CategoryTree.
set this to "on" to hide all translations pages corresponding to the pages pertaining to the category, i.e. notranslations="on" (since Gerrit change 526234, November 2019). This is disabled by default. When set to "on", instead of showing e.g. (Page, Page/en, Page/fr, Page/de, it will show only the default one "Page" and suppress all it's translations).
This doesn't affect "showcount", so still a bug.
a list of namespaces from which pages should be shown in the tree (since r36864, July 2008). The entries in the list must be namespace names, separated by spaces. The main namespace can be represented by "-" or "0". Subcategories will be shown only if Category namespace is present on the list.
class, style, id, etc
The <categorytree> tag supports all standard HTML attributes for block elements (since r36864, July 2008; before that, only style was supported).

Notes on the 'namespaces' parameter[edit]

Category is a namespace. Categories are shown in all modes by default, but specifying the namespaces parameter hides them just like any other namespace not present on the list. If you want to list pages in a given namespace, including pages in subcategories, simply add Category to the namespace list.


  • Listing main namespace pages in Category:Manual:
<categorytree mode="pages" namespaces="Main">Manual</categorytree>
  • Listing main namespace pages and subcategories in Category:Manual:
<categorytree mode="pages" namespaces="Main Category">Manual</categorytree>

The mode parameter is overridden by namespaces:

  • if only Category namespace is asked, it's equivalent to mode=categories;
  • if file namespace is present on the list, it will imply mode=all;
  • otherwise mode=pages will be used. It means that if the site configuration hasn't been changed, the following are equivalent (the first two are always equivalent, the third only if $wgCategoryTreeDefaultMode is the default CategoryTreeMode::CATEGORIES):
<categorytree mode="categories">Manual</categorytree>
<categorytree namespaces="Category">Manual</categorytree>

The {{#categorytree}} parser function[edit]

Since r25825 (Sep 13, 2007), you can also use parser function syntax to place a category tree on a page. This works just like the <categorytree> tag, using a different syntax, e.g. {{#categorytree:Foo}}; options can be specified using the syntax for named template parameters, e.g. {{#categorytree:Foo|hideroot|mode=pages}}.

Using the parser function syntax has the advantage that it allows you to use magic words, templates and template parameters when specifying the category to show. Some examples:

  • Using a magic variable to show "this pages" category tree (may be useful on category description pages): {{#categorytree:{{PAGENAME}}}}.
  • Using a template to specify the category: {{#categorytree:{{root category}}}} - the name of the root category would be defined by the contents of Template:Root_category.
  • Using a template parameter to specify the category, when using CategoryTree inside a template: {{#categorytree:{{{1}}}}} in Template:Baz can be called using {{Baz|Foo}}.

The Special:CategoryTree page[edit]

The special page is called Special:CategoryTree; there you can enter the name of a category and then browse its content.


There are some options you can specify in your LocalSettings.php file.

You can no longer use CT_* constants in LocalSettings.php. Instead use 0 for category mode, 10 for pages, 20 for all, 100 for parents.
maximum number of children shown in a tree node. Default is 200.
enable <categorytree> tag. Default is true.
loads the first level of the tree in a <categorytree> dynamically. This way, the cache does not need to be disabled. Default is false.
disables the parser cache for pages with a <categorytree> tag, or provides max cache time in seconds. Default is 21600 which is 6 hours.
enable HTTP cache for anon users. Default is false.
do not show the namespace name for pages and categories. Default is false, namespaces are shown unless showing categories only. Deprecated as of r36864, July 2008: use $wgCategoryTreeDefaultOptions['hideprefix'] instead.
an array defining the maximum depth for each mode, to which the tree may be expanded initially using the depth parameter in a <category> tag. By default, this is set to 2 for the "categories" mode, and 1 for other modes. To set it to 3 for categories and 2 for other modes, for example, you can use $wgCategoryTreeMaxDepth = [10 => 2, 20 => 2, 0 => 3, 100 => 2];.
the default mode to use when no mode attribute is specified in a <categorytree> tag. May be 0 (the default - categories), 10 (pages), or 20 (all).
the mode to use when rendering trees on category pages. Deprecated as of r36864, July 2008: use $wgCategoryTreeCategoryPageOptions['mode'] instead.
if true, forces the scripts needed by CategoryTree on every page, instead of on-demand. This may be needed if a CategoryTree is embedded in an unusual way, for example in a custom skin or in a system message (since r36888, July 2008).
root category to use for integrating the category tree in the sidebar (since r36920, July 2008). If not set, no tree is integrated (this is the default). Integrating a CategoryTree into the sidebar only works with skins based upon SkinTemplate, that is, Modern, Monobook, Chick, Simple, and MySkin, but not Standard, Nostalgia or CologneBlue.
default options to apply, as an array (since r36864, July 2008). The available options are described above. Example: $wgCategoryTreeDefaultOptions['mode'] = 'pages';.
options to use on category pages, as an array (since r36864, July 2008).
options to use on Special:CategoryTree, as an array (since r36864, July 2008).
options to use when showing the tree in the sidebar, as an array (since r36920, July 2008)

System messages[edit]


By default, when listing subcategories on a category page, each subcategory is followed by an integer, indicating how many subcategories lie beneath it, how many pages it contains, and how many files are in the category (if applicable):

My category name (5 C, 2 P, 1 F)

You can change this behavior by overriding the system message MediaWiki:Categorytree-member-num. It takes five parameters:

Parameter Meaning
$1 Number of subcategories
$2 Number of articles (not including category pages or file pages)
$3 Number of uploaded files
$4 Total number of member pages, including category pages and file pages
$5 Something close to ($1 C, $2 P, $3 F) but with anything that is 0 omitted.

More precisely, a comma separated list of the number of pages (mediawiki:categorytree-num-pages), subcategories (mediawiki:categorytree-num-categories), and files (mediawiki:categorytree-num-files) in the category, or empty (mediawiki:categorytree-num-empty) in the case the category has no members. In versions prior to those around 1.19 this value was different. See older version of these docs.

The default value is ($5).

Tip: Use the ParserFunctions extension to provide if/then/else logic to display different parts conditionally. For example:

{{#ifeq:$1|0||$1 categories}}

A configuration to manage commas and spaces when outputting all info:

Abbreviation version:

({{#ifeq:$4|0|empty|{{#ifeq:$1|0||$1 C{{#ifeq:{{#expr:$3+$2}}|0||,}}}} {{#ifeq:$2|0||$2 P{{#ifeq:$3|0||,}}}} {{#ifeq:$3|0||$3 F}}}})

Full name version:

({{#ifeq:$4|0|empty|{{#ifeq:$1|0||$1 categories{{#ifeq:{{#expr:$3+$2}}|0||,}}}} {{#ifeq:$2|0||$2 pages{{#ifeq:$3|0||,}}}} {{#ifeq:$3|0||$3 files}}}})


Wiki is broken after installing CategoryTree[edit]

  • Turn on error reporting
  • Make sure you have all files installed
  • Make sure all of the CategoryTree extension files have mode 644, and the CategoryTree directory has mode 755.

Options in LocalSettings.php have no effect[edit]

  • Make sure you specify the options after including the extension.

Clicking the has no effect, gives a JavaScript error or just sits on loading[edit]

  • Note that using the <categorytree> tag in system messages (MediaWiki namespace) may not work as expected - this is a known caveat. For a workaround, see Using CategoryTree in the Sidebar below.
  • Make sure you have $wgUseAjax = true; in your LocalSettings.php before including the extension.
  • Make sure you are using the latest version of the extension - the bleeding edge is at [1]
  • If you are using rewrite rules or aliasing (e.g. to have "very short URLs" - i.e. wiki pages in the document root or perhaps redirecting to a www-version of the requested URL), make sure you have an exception in place for the /extensions directory, just like you would for the /skins directory. Also see below.

Clicking the shows no sub-categories error[edit]

  • Try to fix this by adding this code to LocalSettings.php: $wgCategoryTreeDefaultOptions['namespaces'] = [ 0, NS_CATEGORY, NS_FILE ];

Browser reports a bad MIME type for CategoryTree.js and/or CategoryTree.css[edit]

  • Make sure your web server uses the correct MIME types for .js and .css files
  • Enter the URLs directly into the browser and see if it is serving the pages at all, and not some error page; especially:
  • If you are using rewrite rules or aliasing (e.g. to have "very short URLs" - i.e. wiki pages in the document root), make sure you have an exception in place for the /extensions directory, just like you would for the /skins directory.

Member counts are wrong, grey arrows are shown instead of [edit]

Since MediaWiki 1.13, CategoryTree can show the number of members of a category, and can show a grey arrow for tree nodes that do not have any children based on that number. This information is based on the new category table. However, populating that table with the current values does not always work when upgrading to 1.13. In that case, run the populateCategory.php maintenance script, if necessary with the --force option.

toggles shown only on the first level of the category tree view[edit]

In case you get only one level depth while visualing the tree, try to set in modules/ext.categoryTree.styles.css file display: none; to display: inline !important;.

The JavaScript intended to switch the tag style is somehow buggy.

Note to bot users[edit]

Bots and scripts that parse the HTML of category pages can use the notree URL parameter to force the traditional output. However, HTML output is generally not stable, so it is recommended to change your script to use the API to fetch category listings and similar.

"Category Not Found" message[edit]

After you implement the CategoryTree plugin and add the code to show the tree, if you see a message that says Category Not Found, you need to add some content in your category pages. The category pages can't be red pages, basically. Click your category names, add some text in the category page, and then your tree should work fine.

Next 200 links do not work with CategoryTree installed[edit]

Make sure the right version of this extension is installed, relative to the version of MediaWiki you have installed. In particular, versions of this extension made for versions of MediaWiki prior to 1.17 are not compatible with MediaWiki 1.17 and greater, and will cause issues where all the paging links on category pages are broken.

No pages are shown when using the "namespaces" parameter[edit]

See above.


Using CategoryTree in system messages and custom skins[edit]

To use the CategoryTree in system messages or the sidebar, that is, to use it as part of the user interface instead of page content, you have to set wgCategoryTreeForceHeaders to true, so that the support scripts are linked on every page (normally, they are only linked "on demand", but that detection does not work for system messages). This works since r36888 (July 2008). If you try this without forcing the scripts to be included, you will find that Clicking the ► has no effect, gives a JavaScript error or just sits on loading.

In older versions of CategoryTree, you have to modify the code to make this work: find the efCategoryTreeParserOutput function in the file CategoryTree.php, and remove the condition; i.e. it should then look like this:

function efCategoryTreeParserOutput( &$outputPage, &$parserOutput )  {
    CategoryTree::setHeaders( $outputPage );
    return true;

Using CategoryTree in the Sidebar[edit]

Using JavaScript[edit]

Since r36920 (July 2008) with MediaWiki 1.13 (r36917), you can integrate a CategoryTree in the sidebar simply by setting $wgCategoryTreeSidebarRoot to the category you want to use as a root. This only works with skins based upon SkinTemplate however, that is, Modern, Monobook, Chick, Simple, and MySkin, but not Standard, Nostalgia or CologneBlue.

If you use $wgHooks['MonoBookTemplateToolboxEnd'][] = 'wfSomeFunc'; in LocalSettings.php to drop your own wikitext article into the Sidebar, and then add CategoryTree items to it, you'll need to set $wgCategoryTreeForceHeaders = true; to ensure that every page works.

If you want the CategoryTree on a different position in the sidebar, you can reference it on MediaWiki:Sidebar as "categorytree-portlet".

For earlier versions of CategoryTree and/or MediaWiki, you'll need to install a mod to MonoBook.php to enable normal wikitext in the sidebar, see Wikitext in side bar --DJ 19:26, 24 January 2008 (UTC)

To append a link "CategoryTree" to your toolbox (sidebar ) add following code to the JavaScript page (e.g. monobook.js) of your skin and customize the URL "w:en:Special:CategoryTree".

function AppendCategoryTreeToSidebar() {
    try {
        var node = document.getElementById( "p-tb" )
        var aNode = document.createElement( 'a' );
        var liNode = document.createElement( 'li' );
        aNode.appendChild( document.createTextNode( 'CategoryTree' ) );
        aNode.setAttribute( 'href' , '[[w:en:Special:CategoryTree]]' );
        liNode.appendChild( aNode );
        liNode.className = 'plainlinks';
        node.appendChild( liNode );
    } catch(e) {
        // lets just ignore what's happened
addOnloadHook( AppendCategoryTreeToSidebar );

A more generic version of this code can be found at Manual:Interface/Sidebar#content of sidebar and toolbox (javascript) .

Step by step if works easy:

$wgCategoryTreeSidebarRoot = 'Category:article_name';
$wgCategoryTreeForceHeaders = true;

Using MediaWiki: namespace pages[edit]

If you want to create a link that goes to the generic categorytree (displayed as Category tree) when you're on a non-category page, and to a particular categorytree (displayed as View as category tree, with foo being the name of the category you're viewing) when you're on a category page:

  • Add to your MediaWiki:Sidebar (right above the SEARCH is a good place) a line, ** sidebarcategorytree-url|sidebarcategorytree
  • Create a [[MediaWiki:Sidebarcategorytree]] with, say: {{#ifeq: {{NAMESPACE}}|Category|View as category tree|Category tree}}
  • Create a [[MediaWiki:Sidebarcategorytree-url]] with, say: {{#ifeq: {{NAMESPACE}}|Category|Special:CategoryTree/{{BASEPAGENAME}}|Special:CategoryTree/Categories}}

Parameters to request[edit]

It is possible to override the default site configuration of "mode" by providing it to as URL parameter. For example

  • //en.wikipedia.org/wiki/Category:MediaWiki - use default mode
  • //en.wikipedia.org/wiki/Category:MediaWiki?mode=0 - use categories mode
  • //en.wikipedia.org/wiki/Category:MediaWiki?mode=10 - use page mode
  • //en.wikipedia.org/wiki/Category:MediaWiki?mode=20 - use all mode
  • //en.wikipedia.org/wiki/Category:MediaWiki?mode=100 - use parent mode