protected function getPersistentContent()
    {
        if (!$this->persistent || null === ($value = $this->getValue())) {
            return '';
        }
        return '<input type="hidden"' . self::getAttributesString(array(
            'name'  => $this->getName(),
            'value' => $value,
            'id'    => $this->getId()
        )) . ' />';
    }
protected function getPersistentContent()
    {
        if (!$this->persistent || null === ($value = $this->getValue())) {
            return '';
        }
        return '<input type="hidden"' . self::getAttributesString(array(
            'name'  => $this->getName(),
            'value' => $value,
            'id'    => $this->getId()
        )) . ' />';
    }
protected function getPersistentContent ( ) { if ( ! $ this -> persistent || null === ( $ value = $ this -> getValue ( ) ) ) { return '' ; } return '<input type="hidden"' . self :: getAttributesString ( array ( 'name' => $ this -> getName ( ) , 'value' => $ value , 'id' => $ this -> getId ( ) ) ) . ' />' ; }
Generates hidden form field containing the element's value

This is used to pass the frozen element's value if 'persistent freeze'
feature is on

@return string
Generates hidden form field containing the element s value