Get error messages from Zend_Form and response as json
===

I'm trying to get error messages from Zend_Form and response as json. What is the best practice of getting Zend_Form errors and replying as json?

    <?
    
    class SomeController extends Zend_Controller_Action {
    
    	public function indexAction() {
    	
    		$form = new Application_SomeForm();
    		if ($form->isValid( $this->getRequest()->getPos() )) {
    			//do something here
    		}		
    		$this->_helper->json($form->getErrorMessages());
    		
    	}
    
    }

I can't get errors via `$form->getErrorMessages()`, but errors are present if tested `print_r($form->gerErrors())`

    Array
    (
        [email] => Array
            (
                [0] => isEmpty
            )
    
        [password] => Array
            (
                [0] => isEmpty
            )
    
        [foreign] => Array
            (
            )
    
        [login] => Array
            (
            )
    
    )


So, my questions are:

**a) How to get all error messages for form?**

**b) Is there any Json Wrapper for resposning ajax submitted forms? For example `$jsonResponse->setErrorStatus()->addFormErrors($form)`**
