improve cancel-button

Hi there,
to theme the cancel button with the module "button style" you need the wrapper around it.
Found this: http://drupal.org/node/133861#comment-4002698
I would add this to the button function :

...
// Javascript case
$form['buttons']['cancel'] = array(
	'#type' => 'submit',
        '#value' => t('Cancel'),
        '#name' => 'cancel_button',
        '#weight' => 20,
       '#post_render' => array('change_button_type'),
       '#prefix' => '     ',
       '#attributes' => array('onClick' => 'history.go(-1); return true;')
	);
break;

function change_button_type($markup, $element) {
    $markup = str_replace('type="submit', 'type="button', $markup);
    return $markup;
}