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

The following plugins are known to handle this event and their source code may be a good start for understanding and implementing a handler yourself.

• metaheaders
• loadskin
• jquery

• Action Plugins
• Events