Help:Transclusion

Transclusion is a powerful MediaWiki feature that allows you to include the content of one page within another page. Instead of copying and pasting content, transclusion dynamically pulls content from a source page, ensuring that updates to the source are automatically reflected everywhere it's used.

What is Transclusion?

Transclusion embeds the content of one wiki page into another. When the source page is updated, all pages that transclude it are automatically updated as well.

Benefits:

Maintains consistency across multiple pages
Reduces duplicate content
Makes site-wide updates easier
Saves time and effort

Basic Syntax

Syntax	Description
`{{PageName}}`	Transclude a page from the Template namespace
`{{:PageName}}`	Transclude a page from the main namespace
`{{Namespace:PageName}}`	Transclude from a specific namespace

Examples

{{Welcome}}             <!-- Transcludes Template:Welcome -->
{{:Main Page}}          <!-- Transcludes the Main Page article -->
{{Help:Contents}}       <!-- Transcludes Help:Contents -->
{{User:John/Signature}} <!-- Transcludes a user subpage -->

Types of Transclusion

Template Transclusion

The most common form. Templates are pages in the Template: namespace designed to be transcluded.

Article Transclusion

Include content from regular articles using a colon prefix:

{{:Article Name}}

Special Namespace Transclusion

Transclude from any namespace by specifying it:

Using Templates

Creating a Template

Create a page titled Template:YourTemplateName
Add your content
Save the page

Example Template:Greeting

Hello and welcome to our wiki! We're glad you're here.

Using the Template

Output:

Hello and welcome to our wiki! We're glad you're here.

Controlling Transcluded Content

You can control which parts of a page are transcluded using special tags:

noinclude

Content inside these tags appears only on the original page, not when transcluded.

This text appears everywhere.
<noinclude>
This text only appears on the template page itself.
[[Category:Templates]]
</noinclude>

includeonly

Content inside these tags appears only when transcluded, not on the original page.

<includeonly>
This text only appears on pages that transclude this template.
</includeonly>

onlyinclude

Only content inside these tags will be transcluded. Everything else is excluded.

This won't be transcluded.
<onlyinclude>
Only this content will be transcluded.
</onlyinclude>
This also won't be transcluded.

Summary Table

Tag	On Template Page	When Transcluded
`<noinclude>`	Visible	Hidden
`<includeonly>`	Hidden	Visible
`<onlyinclude>`	Visible	Visible (only this content)

Parameters

Templates can accept parameters to customize their output.

Unnamed Parameters

Template:Greeting

Hello, {{{1}}}! Welcome to {{{2}}}.

Usage:

{{Greeting|John|our wiki}}

Output:

Hello, John! Welcome to our wiki.

Named Parameters

Template:UserInfo

'''Name:''' {{{name}}}
'''Role:''' {{{role}}}
'''Joined:''' {{{joined}}}

Usage:

{{UserInfo|name=Jane Smith|role=Editor|joined=January 2024}}

Default Values

Provide fallback values if a parameter isn't supplied:

Hello, {{{name|Guest}}}!

If name is not provided, it displays "Guest".

Checking if Parameter Exists

Using parser functions:

{{#if:{{{image|}}}|[[File:{{{image}}}]]|No image available}}

Substitution vs Transclusion

Transclusion

{{Template}}

Content is dynamically pulled each time the page loads
Updates to template automatically appear everywhere
Use for content that should stay synchronized

Substitution

{{subst:Template}}

Content is copied and permanently inserted
Changes to template do NOT affect substituted content
Use for one-time insertions (like welcome messages)

{{subst:Welcome}}    <!-- Substitutes content permanently -->

Common Examples

Navigation Box

Template:ProjectNav

<div class="navbox">
'''Project Navigation'''
[[Project:About|About]] | [[Project:Guidelines|Guidelines]] | [[Project:Help|Help]]
</div>
<noinclude>
[[Category:Navigation templates]]
</noinclude>

Infobox

Template:Infobox Person

{| class="infobox"
|-
! colspan="2" | {{{name|Unknown}}}
|-
| '''Born''' || {{{birth_date|Unknown}}}
|-
| '''Occupation''' || {{{occupation|Unknown}}}
|}
<noinclude>
==Usage==
{{Infobox Person
|name=
|birth_date=
|occupation=
}}
[[Category:Infobox templates]]
</noinclude>

Warning/Notice Boxes

Template:Warning

<div class="warning-box" style="background:#ffe0e0; border:1px solid red; padding:10px;">
⚠️ '''{{{1|Warning}}}'''
</div>

Usage: {{Warning|This article contains spoilers}}

Stub Template

Template:Stub

<div class="stub">
''This article is a stub. You can help by [{{fullurl:{{FULLPAGENAME}}|action=edit}} expanding it].''
</div>
<includeonly>
[[Category:Stub articles]]
</includeonly>
<noinclude>
[[Category:Notice templates]]
</noinclude>

Troubleshooting

Common Issues

Problem	Cause	Solution
`{{Template}}` shows as text	Template doesn't exist	Create the template page
Content not appearing	Wrong namespace	Use correct prefix (`:` for main namespace)
Parameters not working	Wrong syntax	Check for typos in `{{{parameter}}}`
Changes not reflecting	Page caching	Purge the page cache
Circular transclusion error	Page includes itself	Remove self-reference

Purging Cache

If changes to a template aren't appearing, purge the cache:

Add ?action=purge to the URL
Or click "Purge" if available in your wiki's interface

Viewing Transcluded Pages

To see which pages transclude a template:

Go to the template page
Click "What links here" in the sidebar
Look for pages that transclude this template

Best Practices

Document your templates - Add usage instructions in <noinclude> tags
Use descriptive parameter names - {{{author}}} is clearer than {{{1}}}
Provide default values - Prevents broken output if parameters are missing
Categorize templates - Keep templates organized
Test before saving - Use the Preview button
Keep templates focused - One purpose per template