Actions cause the provider to perform a task and return results.
To specify the action the provider should perform, supply action=xxx, where xxx is the action name.
Also specify any additional parameters that the action needs. For example, all actions except User.Login must have the parameter User.context parameter specified so that the servlet can associate the request with the session.
Providers should check for the action parameter to determine the action to be performed. However, the servlet cannot ensure that any provider actually uses the action parameter.