updateAddForm.ctp

<?php
$formHtml = $this->Form->create('Release', array('id' => 'add-track-form', 'type' => 'file', 'action' => 'add'));

$this->Form->input('Release.release_category_id', array('label' => 'Category'));
$this->Form->input('Release.published');
$this->Form->input('Release.artist');
$this->Form->input('Release.title');
$this->Form->input('Release.label');
$this->Form->input('Release.year');

$this->Form->input('ReleaseCover.file', array('type' => 'file', 'label' => 'Cover'));

$fieldsets = array();
for($i = 0; $i < $numberOfTracks; $i ++)
{
    $fieldsets[] = $this->element('releases/add_track', array('i' => $i));
}

$formHtml .= $this->Form->end(__('Submit', true));
$formData = Set::reverse(new Xml($formHtml));

$data = array
(
    'token' => array
    (
        'key' => array
        (
            'id' => $formData['Form']['Div'][0]['Input'][1]['id'],
            'value' => $formData['Form']['Div'][0]['Input'][1]['value']
        ),
        'fields' => array
        (
            'id' => $formData['Form']['Div'][2]['Input']['id'],
            'value' => $formData['Form']['Div'][2]['Input']['value']
        )
    ),
    'fieldsets' => $fieldsets
);

echo $this->Js->object($data);
?>