public function getRequestVar($sVarName, $sRequestType = null)
    {
        $sValue = null;
        switch ($sRequestType) {
            case 'post':
                if (isset($_POST[$sVarName])) {
                    $sValue = $_POST[$sVarName];
                }
                break;
            case 'get':
                if (isset($_GET[$sVarName])) {
                    $sValue = $_GET[$sVarName];
                }
                break;
            case 'cookie':
                if (isset($_COOKIE[$sVarName])) {
                    $sValue = $_COOKIE[$sVarName];
                }
                break;
            default:
                if ($sValue === null) {
                    $sValue = $this->getRequestVar($sVarName, 'post');
                }

                if ($sValue === null) {
                    $sValue = $this->getRequestVar($sVarName, 'get');
                }

                if ($sValue === null) {
                    $sValue = $this->getRequestVar($sVarName, 'cookie');
                }
                break;
        }

        return $sValue;
    }