可以用firebug或者chrome的工具来查看网页的Response Headers：
Response Headers
HTTP/1.1 200 OK 
Date: Thu, 29 Nov 2012 01:08:16 GMT 
Server: Apache/2.2.15 (CentOS) 
X-Powered-By: PHP/5.2.17 
Connection: close 
Transfer-Encoding: chunked 
Content-Type: text/html; charset=UTF-8