private function getCssArray() {
        if (!$this->hasRequestParameter('cssJson')) {
            throw new common_exception_MissingParameter('cssJson', __CLASS__.'::'.\Context::getInstance()->getActionName());
        }
        $cssArr = json_decode($_POST['cssJson'], true);
        if(!is_array($cssArr)) {
            throw new common_exception_InvalidArgumentType(__CLASS__,\Context::getInstance()->getActionName(), 0, 'json encoded array');
        }
        return $cssArr;

    }