Cookie：预期时未看到标头

Question

我正在使用 FireFox 的 HTTP Live 标头来查看标头。 我在 mydomain.com 上写了一个脚本，它只是设置了一个测试 cookie。 我认为当我们向裸 URL http://mydomain.com/script.php 发送请求时，cookie 会发送到所有子域。 但是当我向http://www.mydomain.com/script.php 发送请求时，浏览器并没有在标头请求中发送cookie。怎么会？

http://mydomain.com/script.php

GET /script.php HTTP/1.1
Host: mydomain.com
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.8pre) Gecko/20100710 Ubuntu/9.10 (karmic) Namoroka/3.6.8pre
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive

HTTP/1.1 200 OK
Server: nginx
Date: Fri, 16 Jul 2010 00:08:11 GMT
Content-Type: text/html
Transfer-Encoding: chunked
Connection: keep-alive
X-Powered-By: PHP/5.2.11
Set-Cookie: UserID=23; expires=Fri, 16-Jul-2010 01:08:11 GMT; path=/
Content-Encoding: gzip
----------------------------------------------------------
http://www.mydomain.com/script.php

GET /script.php HTTP/1.1
Host: www.mydomain.com
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.8pre) Gecko/20100710 Ubuntu/9.10 (karmic) Namoroka/3.6.8pre
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive

HTTP/1.1 200 OK
Server: nginx
Date: Fri, 16 Jul 2010 00:08:24 GMT
Content-Type: text/html
Transfer-Encoding: chunked
Connection: keep-alive
X-Powered-By: PHP/5.2.11
Set-Cookie: UserID=23; expires=Fri, 16-Jul-2010 01:08:24 GMT; path=/
Content-Encoding: gzip
----------------------------------------------------------

是不是较新的浏览器没有像以前那样发送标头？

Answer 1

添加域选项domain=.mydomain.com。这对应setcookie的域参数，这里有解释：

"使 cookie 在所有用户上都可用 example.com 的子域，那么你会 将其设置为 '.example.com'。”