I am tring to use an ajax post to an action. GET requests work fine but when I try to POST I see a \'400 Bad Request\' in firebug and the view return a \'Black hole\' response.<
FYI CakePHP 2.3 and above now includes unlockedActions just for this purpose to be used in beforeFilter in your controller, or AppController.
$this->Security->unlockedActions = array('ajaxAction');
From: http://book.cakephp.org/2.0/en/core-libraries/components/security-component.html#disabling-security-component-for-specific-actions