TPL_METAHEADER_OUTPUT

This event is signalled by tpl_metaheaders() in inc/template.php after preparing the default meta headers. You can use it to manipulate the meta headers before they're sent to the browser.

$data is a two-dimensional array of all meta headers. The keys are meta, link and script.

Here is an example for using the data property to add meta information, stylesheets and JavaScript

// Adding a meta value
$event->data["meta"][] = [
    "name" => "DC.Subject",
    "content" => "Some information"
];
 
// Adding a stylesheet 
$event->data["link"][] = [
    "type" => "text/css",
    "rel" => "stylesheet", 
    "href" => DOKU_BASE . "lib/plugins/myplugin/specialstyle.css"
];
 
// Adding a JavaScript File
$event->data["script"][] = [
    "type" => "text/javascript",
    "src" => DOKU_BASE . "lib/plugins/myplugin/javascript_library.js",
    "_data" => ""
];
 
// Adding JavaScript Code
$event->data["script"][] = [
    "type" => "text/javascript",
    "charset" => "utf-8",
    "_data" => "addInitEvent(function(){comments_addButtons('$ID');});"
];

Note:

• When you are adding the stylesheet or javascript file for compatibility with using slash as namespace separator in URLs you should prepend the file link with DOKU_BASE.
• For adding the javascript file you should specify an empty _data field for generating of a closing “script” tag, otherwise you get an incorrect self closed “script” tag.
• You may use other tags as well

$event->data['style'][] = [
    'type'  => 'text/css',
    '_data' => 'a {color: blue;}'
];

• Code related to this event used in any DokuWiki's files, plugins and templates
• Action Plugins
• Events