airtime_nginx_php7/airtime_mvc/application/forms/AddShowStyle.php

<?php

class Application_Form_AddShowStyle extends Zend_Form_SubForm
{

    public function init()
    {
       // Add show background-color input
        $this->addElement('text', 'add_show_background_color', array(
            'label'      => _('Background Colour:'),
            'class'      => 'input_text',
            'filters'    => array('StringTrim')
        ));

        $bg = $this->getElement('add_show_background_color');

        $bg->setDecorators(array(array('ViewScript', array(
            'viewScript' => 'form/add-show-style.phtml',
            'class'      => 'big'
        ))));

        $stringLengthValidator = Application_Form_Helper_ValidationTypes::overrideStringLengthValidator(6, 6);
        $bg->setValidators(array(
            'Hex', $stringLengthValidator
        ));

    // Add show color input
        $this->addElement('text', 'add_show_color', array(
            'label'      => _('Text Colour:'),
            'class'      => 'input_text',
            'filters'    => array('StringTrim')
        ));

        $c = $this->getElement('add_show_color');

        $c->setDecorators(array(array('ViewScript', array(
            'viewScript' => 'form/add-show-style.phtml',
            'class'      => 'big'
        ))));

        $c->setValidators(array(
                'Hex', $stringLengthValidator
        ));
    }

    public function disable()
    {
        $elements = $this->getElements();
        foreach ($elements as $element) {
            if ($element->getType() != 'Zend_Form_Element_Hidden') {
                $element->setAttrib('disabled','disabled');
            }
        }
    }

}