Plugin Events that can apply on backend - Joomla! Forum - community, help and support

hi all

i trying write plugin runs before displaying menu manager (backend). not pro on programming wrote hello world plugin test if plugin works want. 2 files shown below.

in end found hello world display on frontend nothing happens on backend. what's wrong? grateful if can point me out if there mistake , tell me correction direction...

in myplugin.php

code: select all

<?php

defined('_jexec') or die;
jimport('joomla.plugin.plugin');

class plgmyplugin extends jplugin
{
   public function oncontentbeforedisplay($context)
   {
      jexit(jtext::_('hello world'));
   }
}


in myplugin.xml

code: select all

<?xml version="1.0" encoding="utf-8"?>
<extension version="3.0" type="plugin" group="content">
   <name>plg_myplugin</name>
   <version>1.0.0</version>
   <description>hello world plugin</description>
   <files>
      <filename plugin="myplugin">myplugin.php</filename>
      <filename>index.html</filename>
   </files>
</extension>


i still struggling on plugin events backend, couldn't find related document version 3, found little 2.5, , blind-testing following events, none applied in backend.

•onafterdispatch() definitions: 3 references: 0
•onafterinitialise() definitions: 4 references: 0
•onafterrender() definitions: 3 references: 0
•onbeforeindex() definitions: 1 references: 0
•onbuildindex() definitions: 1 references: 0
•oncontentbeforedisplay() definitions: 2 references: 0
•oncontentprepare() definitions: 4 references: 0
•ondisplay() definitions: 8 references: 1
•ongetcontent() definitions: 3 references: 0
•oninit() definitions: 4 references: 0
•onloadinit() definitions: 1 references: 0
•onsave() definitions: 3 references: 0
•onsetcontent() definitions: 3 references: 0
•onstartindex() definitions: 1 references: 0

i know events onuserauthenticate , used editors works in backend, cannot imagine there isn't oncontentprepare backend...