remove validation zend form element javascript/jquery - php

Question

I want to disable the validation on one of the zend form element based on the input on another element on the same form. I need to achieve this using javascript/jquery. Something very common but very surprisingly couldn't find it over the internet.
e.g.
In the controller:
$oFormMassEdit = new Account_Form_Returns_Return();
$this->view->form = $oFormMassEdit;
In Account_Form_Returns_Return's constructor:
$oNoteElement = new Zend_Form_Element_Textarea('option', array(
'required' => true,
));
$this->addElemet($oNoteElement)
$oReasonElement = new Zend_Form_Element_Select('note', array(
'multiOptions' => array (
'return' => 'return',
'defect' => 'Kaput',
'other' => 'Anderer Grund'
),
'required' => true,
));
$this->addElement($oReasonElement);
$this->addDisplayGroup(array('note', 'option'), 'main', array('legend' => 'Retouren'));
$this->addElement('button','send', array(
'type' => 'submit',
'label' => 'Methode speichern',
));
and finally in the view,
<?= $this->form; ?>

Answer 1

Javascript can't (not in a sensible way) switch Zend_Form configuration. What you can do is changing the 'required' param for certain form fields on validation. For example; If you want to allow fieldTwo to be empty if fieldOne has 'desiredValue' as value you can achieve this using the following function in your form:
public function isValid($data) {
if('desiredValue' == $data['fieldOne'])) {
$this->getElement('fieldTwo')->setRequired(false);
}
return parent::isValid($data);
}