How to override Joomla System Messages - message.php template
joomla, joomla2.5, joomla3.1
Solution
For Joomla! 1.7 - 2.5
You need copy `libraries/joomla/document/html/renderer/message.php` in to `templates/YOUR_TEMPLATE/html/message.php`
Then in index.php of YOUR_TEMPLATE you need to include the file (as it is not automatically included like other overrides):
// Message overwrite
require_once JPATH_ROOT .'/templates/'. $this->template .'/html/message.php';
Now you can safety overwrite the `JDocumentRendererMessage::render()` function there ;)
For Joomla! 3.x
You just need make html/message.php file in YOUR_TEMPLATE. This file should contain function renderMessage(). Check the isis default template, as example.
Problem
Joomla by default renders its system messages (errors, notices etc.) in `libraries/joomla/document/html/renderer/message.php`. For my own template, I would like to customize the way these messages are displayed. However it does not seem to be possible in the traditional way, using template overrides. Is anyone here aware of a way to accomplish something like this?