Changes the color depending on the message needed. Each has its own preset image, see #Examples
notice
optional
image
left image
Override the image (“none” for no image). Use format: [[File:Commons-emblem-urgent.svg|class=noviewer|48px]]. The default depends on the type.
empty
optional
imageright
right image
Show an image on the right side, similar to the left one (but empty by default).
empty
optional
textstyle
text style
Override/augment default style of text cell (e.g. alignment — text-align:left; / text-align:right; / text-align:center;).
empty
optional
style
box style
Override/augment default style of the whole message box.
empty
optional
class
box class
Augment default CSS classes of the whole message box. Particularly useful if your template uses TemplateStyles.
empty
optional
lang
language
Set the language of the text – it's important for right-to-left languages: their image is on the right and imageright is on the left. It helps assistive software (e.g. screen readers) even in left-to-right languages.
empty
optional
width
box width
Set the width of the box (avoid using it, 80% for example is too large as it leaves only 10% of the page content width for the left/right margins where there may be floating elements generally large of about 250px: if this occurs the Mbox will be displayed at a much lower position on the page, as if there was a "clear:both", so Mbox may not be immediately visible without scrolling down the page with a huge blank space in the middle and all the rest of the page after the Mbox will be also invisible without scrolling). Instead, use the "margin" parameter to set horizontal margins.
To avoid the centering, and/or the thick left border, modify e.g. “style=margin-left:0;border-left:2px solid #F4C430”
auto
optional
margin
horizontal margin
Set the horizontal margin of the box (by default it is "auto" if a legacy width is specified, otherwise it is "10%").
TemplateData is a way to store information about template parameters (the description of those and of the whole template) for both humans and machines. It is used by VisualEditor and possibly other tools like Upload Wizard.
Existing template documentation
At Wikimedia Commons, it is recommended to use {{TemplateBox}} with either useTemplateData=1 or useTemplateData=only on the /doc subpage and transcluding it with {{Documentation}} into the template. <nowiki>-tags can be wrapped around the arguments, if required, to avoid templates being expanded.
Newly created template documentation and imports
Another option, especially for imported templates, or for users with JSON experience, is placing raw <templatedata>-tags into the Wikitext of the template, as described in various Wikipediae.
The icon displayed in the message box is clickable and drives to Commons (to see its attributions), but only when the message box is displayed in a "Template:" page (including their talk pages). When the template is displayed in a page belonging to all other namespaces, no link is generated, only the icon is visible directly.
Examples
All possible values for parameter "type"
type=(empty) → default (synonym tonotice)
type=notice → for informative messages only
type=message → for informative messages only
This message box is using an invalid "type=message" parameter and needs fixing.
type=query → for minor issues
This message box is using an invalid "type=query" parameter and needs fixing.
type=style → for cleanup (synonym toquery, only different icon)
type=issue → for larger issues
This message box is using an invalid "type=issue" parameter and needs fixing.
type=content → for content issues (synonym toissue)
type=serious → for serious notices
This message box is using an invalid "type=serious" parameter and needs fixing.
type=delete → for deletion notices (synonym toserious)
type=stop → for stop and other caution notices, such as frequent issues (synonym toserious, only different icon)
This message box is using an invalid "type=stop" parameter and needs fixing.
type=speedy → for speedy deletion notices
type=warning → for urgent notices (synonym tospeedy)
This message box is using an invalid "type=warning" parameter and needs fixing.
type=move → for move requests
type=protection → for protection notices (synonym tomessage, only different icon)
type=license → for licenses
This message box is using an invalid "type=license" parameter and needs fixing.
type=legal → for legal disclaimers such as {{Trademark}}
This message box is using an invalid "type=legal" parameter and needs fixing.
type=honor → for honors such as featured image
This message box is using an invalid "type=honor" parameter and needs fixing.
type=growth → for other "good" notices
This message box is using an invalid "type=growth" parameter and needs fixing.
type=shit → for fun ... or for maintenance affairs :)
This message box is using an invalid "type=shit" parameter and needs fixing.
Examples with more parameters
type = (empty) and style = background:#DFF
type = query and image = [[File:Warning.svg|alt=Exclamation mark|30px|class=noviewer]]
This message box is using an invalid "type=query" parameter and needs fixing.
type = query and image = [[File:OOjs UI icon alert-yellow.svg|alt=Exclamation mark|40px|class=noviewer]]
This message box is using an invalid "type=query" parameter and needs fixing.
type = query and image = [[File:Lol exclam.png|alt=Exclamation mark|38px|class=noviewer]]
This message box is using an invalid "type=query" parameter and needs fixing.
type = issue, image = [[File:Commons-emblem-hand-orange.svg|alt=Stop hand|45px|class=noviewer]] and style = background:#f7f7f7;
This message box is using an invalid "type=issue" parameter and needs fixing.
type = message, image = [[File:Pictogram voting info.svg|20px|class=noviewer]] and margin = 0em
This message box is using an invalid "type=message" parameter and needs fixing.
type = growth, image = none and style = margin: 10px 0 10px 0 (top right bottom left)
This message box is using an invalid "type=growth" parameter and needs fixing.