public function display_data() {
        // Default formatting.
        $data = parent::display_data();

        // Are we creating a link?
        if (!empty($this->field->param4) and !empty($data)) {

            // Define the target.
            if (! empty($this->field->param5)) {
                $target = 'target="'.$this->field->param5.'"';
            } else {
                $target = '';
            }

            // Create the link.
            $data = '<a href="'.str_replace('$$', urlencode($data), $this->field->param4).'" '.$target.'>'.htmlspecialchars($data).'</a>';
        }

        return $data;
    }