In addition to the onPrepareContent event we just used, plug-ins in Joomla! can respond to many different kinds of events during a request. Multiple plug-ins can respond to any one event in their group. The ordering of the plug-ins in Joomla!'s back end determines the order in which registered functions are called. For instance, if both plug-in A and plug-in B respond to onBeforeDisplayContent, if A's function is registered with onBeforeDisplayContent before B's function is, then A will be called first. Here is a listing of when these events occur, grouped by plug-in type:
onAfterInitialise after the framework loads, but before routing and output
onAfterRoute after routing, but before output
onAfterDispatch after the Joomla! application is started
onAfterRender after all output is processed
onGetWebServices when the XML-RPC function requests a list of valid function calls
onLoginFailure when a login attempt fails