Help:A quick guide to templates

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This is a quick overview of templates. Full details can be found in Help:Template and m:Help:Advanced templates.

A template allows you to reproduce infinite content.

Templates are pages in the template namespace. This means any page whose title begins with "Template:", such as "Template:foo", can be used as a template. The content of a template titled Template:templatename, can be added to a page by typing {{templatename}} while editing the page. When the page is later viewed, {{templatename}} is replaced by the content of the page "Template:templatename". If the page "Template:templatename" is later altered, all the pages with {{templatename}} in them will change automatically.

Among other things, templates are used to add recurring messages to pages in a consistent way, to add boilerplate messages, and to create navigational boxes.

When a template is automatically expanded and appears on a page, it is said to be "transcluded".

Templates are documented (or should be) at their pages. Thus if you want to know how to use a template whose name is "foo" (perhaps because you've seen {{foo|...}} in the source of an article), then go to "Template:foo". (The documentation itself will usually be located at "Template:foo/doc", but will be transcluded onto the "Template:foo" page).

Creating, editing and using templates[edit]

You start a new template in the same way you would start an article page. The only difference is that its title must start with Template:.

Once you have made the template, for example Template:templatename, you can add {{templatename}} to the pages you want to use it on. Every page using this template uses the same boilerplate text, each time a user visits it. When the template is updated, all pages containing the template tag are automatically updated.

Alternatively, you can add {{subst:templatename}} to the pages you want to use the boilerplate text on. The system fetches a one-time copy of the template text, and substitutes it into the page, in place of the template tag. If anyone edits the template afterwards, pages that used the subst: keyword do not update. Sometimes that is what you want.

If the template you want to edit looks like {{foo}}, you would go to Template:foo to edit it. To get there, type "Template:foo" in the search box (see search), or make a wikilink like [[Template:foo]] somewhere, such as in the sandbox, and click on it.

Once you are there, just click "edit" or "edit this page" and edit it in the same way you would any other page. You can add anything you would add to a normal page, including text, images and other templates. Please be aware that your edit might affect many pages, so be cautious.

Parameters[edit]

Templates can have parameters. Instead of just the template name, like {{foo}}, a template with parameters will have additional text, separated by vertical bars (|), e.g. {{foo|July|lc=yes}}. Here July is the value of the first unnamed parameter; yes is the value of the named parameter lc. Writing the template page for a template with parameters is more complicated than for a template with no parameters. See Help:Template.

FAQ[edit]

How can I find out how to use an existing template? 
To see the documentation for the template whose name is "foo", go to "Template:foo".
Can I use a template in more than one project? 
No, if you want to use it on two different language Wikipedias, for example, you would need to create it twice.
Are templates case-sensitive? 
Yes, except usually the first letter.
Can I add parameters? 
Yes, see Help:Template for instructions.
How many templates can I use in a page? 
A lot, but it depends on how they work. (In older versions you could not use the same one more than 5 times). There is a limit on the number of template expansions allowed during the creation of a page. If the templates you put on the page use other templates when they are expanded it's possible to exceed the limit. See WP:UNNEST.
I edited the template, so why didn't the page it is used on change? 
Wikipedia and your computer both store caches – or saved copies – and don't always show you an updated page. First, try to bypass your browser's cache by pressing Ctrl and F5. If that fails, you need to purge the page's cache (which can be done several different ways). Perhaps the easiest way to do this is by clicking edit on the page in which the template appears, and then clicking on Save page without having changed anything – there is no need to fill in the Summary field since there will not be any history of this as a change generated.
Can I move a template to a new name? 
Yes, this works in exactly the same way as normal page moves. When a page called for inclusion is a redirect page, the redirect target is included instead.
Can I use a template within a template? 
Yes.
How do I add a new template?
You start a new template in the same way you would start a normal page. The only difference is that its title must start with Template:. Don't forget to document it so that other editors can use it!
Where is the manual for the programming language used to write templates?
The language inside templates is the same language as regular wiki markup, but template writers tend to use the more complex available functions such as #if: statements. See Wikipedia's Help:Template, Wikimedia's mw:Help:Template, and all of the "advanced functioning" help pages listed toward the bottom of mw:Help:Template#Links to other help pages.

Examples[edit]

Wikipedia-specific help[edit]