Parameters

An include can pass values into the included page. Parameters are separated by pipes; the included page reads them with triple braces.

Passing parameters

Positional parameters are just values, counted from 1:

{{Colorlink|Rome|crimson}}

Named parameters use name="value" — the value in quotes:

{{Collapse|text="Spoilers below"}}

The quotes are the engine’s convention for named values, and the editor’s checker enforces them. They earn their keep: a quoted value may contain pipes and equals signs freely (text="a | b = c"), and \" puts a literal quote inside.

Rules worth knowing:

• Whitespace around names and values is trimmed: {{Greet| hi }} passes hi.
• A positional value cannot contain a bare = — the first = turns the part into a named parameter. Passing a URL positionally? Name it by its number instead, unquoted: {{Link|1=https://example.com?a=b}}.
• An empty value is a real value: {{Box|title=}} passes an empty title (which overrides a default — see below).
• If the same name is given twice, the last one wins.
• Values may themselves be includes: {{Box|content={{Other page}}}} renders Other page and passes the result.

Reading parameters (template authors)

Inside the included page, triple braces substitute the value:

{{{1}}}          the first positional value
{{{title}}}      the named value "title"
{{{title|News}}} with a default when the caller didn't supply one

• A parameter that was supplied but empty beats the default: {{Box|title=}} renders an empty title, not “News”.
• A parameter that was not supplied and has no default renders as nothing.
• Defaults can nest: {{{3|{{{1}}}}}} means “the third value, or else the first” — the stock Colorlink template uses exactly this to make its label optional.

Implicit parameters

The engine injects two parameters into every include, mainly for templates that generate HTML ids:

{{{_uid}}} exists because DOM ids must be unique: the stock Collapse template keys its show/hide toggle on it, so seven collapses on one page get seven working toggles.