17 
Method(HEAD)

URIで示す実体のヘッダだけを要求(BODY は転送しない)
    例：
            HEAD / HTTP/1.1
            Host: cat.csce.kyushu-u.ac.jp

            HTTP/1.1 200 OK
            Date: Thu, 08 Nov 2001 10:52:46 GMT
            Server: Apache/1.3.19 (Unix)  (Vine/Linux)
            Last-Modified: Tue, 06 Nov 2001 11:40:17 GMT
            ETag: "5b1be-d9-3be7cc21"
            Accept-Ranges: bytes
            Content-Length: 217
            Content-Type: text/html