Manual talk:Hooks/OutputPageBeforeHTML

500 Server Error
When attempting to add text to $wgOut or parameter 1, an infinite loop is created. I guess that's why there's a disclaimer on the article page warning us to use at our own risk. But the second parameter is up for grabs. -- Egingell 12:10, 16 August 2007 (UTC)

It seems as if the first parameter is an OutputPage object rather than a ParserOutput object. (at least in version 1.6.3)

Simple Example
A simple example for using this hook is found in Extension:PatchOutput.

Problem with wfMsg
In mediawiki 1.15.5, in the function called by the hook, the function wfMsg doesn't work for registered users: a call to  returns:
 * the text defined in the i18n file for unregistered users
 * for registered users

What is the reason of this behaviour? 85.20.218.75 06:35, 10 July 2011 (UTC)