    public function validate($string, $config, $context) {

        $string = $this->parseCDATA($string);

        if ($string === '') return false;
        $length = strlen($string);
        if ($length === 1) return false;
        if ($string[$length - 1] !== '%') return false;

        $number = substr($string, 0, $length - 1);
        $number = $this->number_def->validate($number, $config, $context);

        if ($number === false) return false;
        return "$number%";

    }
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.