sanitize input

    /*
    - Sanitize Input
    - Helps reduce security risks and minimalises the possibility of SQL injection.

    $string     - The string you wish to sanitize before entering into the database.
    $level      - The level of security:
                   > 1 = adds slashes to prevent SQL injection
                   > 2 = adds slashes + htmlspecialchars to turn HTML tags into
                         HTML entities (eg. <html> becomes &lt;html&gt;)
                   > 3 = add slashes + strip_tags to remove all HTML tags.
    */

    public function sanitizeInput($string, $level = 1) {

        switch ($level) {
        case 1:
            $string = addslashes($string);
            break;
        case 2:
            $string = htmlspecialchars(addslashes($string));
            break;
        case 3:
            $string = strip_tags(addslashes($string));
            break;
        }

        return $string;

    }