如何增加或者减少destoon验证码的数目，找到/include/captcha.class.php中的如下代码

function captcha() {
$this->func = true;
$this->chars = ‘abcdeghkmnpqstwxyz234789ABCEFGHJKLMNPRSTWXYZ’;
//$this->chars = ‘123456789’;
$this->length = 6;
$this->ck_func();