Post to an action URL fails, Get works
I believe that when you post data using name='action' from a form that craft automatically uses the actionUrl to route the request properly, so that if your controller is here:

/craft/plugins/broadbean/controllers/Broadbean_JobsController.php


with a method actionNew, then craft will create the action route broadbean/jobs/new automatically:

&lt;input type="hidden" name="action" value="broadbean/jobs/new"&gt;


On the other hand if you are linking directly then craft doesn't know to use the action route, so you need to explicitly tell it that this is an action request:

&lt;a href="{{ actionUrl('broadbean/jobs/new', { id: 10 }) }}"&gt;


or from javascript:

var url = Craft.getActionUrl('broadbean/jobs/new', { id: 10 });


If you were to call the action externally then you would have to write the full action url without the benefit of using the automatic config routing:

http://mysite.com/actions/broadbean/jobs/new?id=10


or, if the admin had, for example, set up a custom actionUrl in the config file:

http://mysite.com/methods/broadbean/jobs/new?id=10