1.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
