private function build($alert = array())
    {
        $str = '';
        $alert = \array_merge(array(
            'alert'         => '',
            'dismissible'   => true,
            'class'         => 'danger',        // success info warning danger
            'framework'     => 'bootstrap',
        ), $alert);
        $alert['class'] = 'alert-'.$alert['class'];
        if ($alert['framework'] == 'bootstrap') {
            if ($alert['dismissible']) {
                $str .= '<div class="alert alert-dismissible '.$alert['class'].'" role="alert">'
                    .'<button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>'
                    .$alert['alert']
                    .'</div>';
            } else {
                $str .= '<div class="alert '.$alert['class'].'" role="alert">'.$alert['alert'].'</div>';
            }
        } else {
            $str .= '<div class="alert '.$alert['class'].'">'.$alert['alert'].'</div>';
        }
        return $str;
    }