Client/Server Request/Response
HTTP is a simple client/server protocol with stateless request/response sequences.

The Client HTTP Request
7 possible HTTP 1.1 request types: GET, PUT, POST, DELETE, HEAD, OPTIONS and TRACE. Any number of HTTP headers can accompany a request.

GET /filename.php HTTP/1.0
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*
Accept-Charset: iso-8859-1,*,utf-8
Accept-Encoding: gzip
Accept-Language: en
Connection: Keep-Alive
Host: localhost
User-Agent: Mozilla/4.77 [en] (X11; U; Linux 2.4.5-pre4 i686; Nav)
The Server HTTP Response
HTTP/1.1 200 OK
Date: Mon, 21 May 2001 17:01:51 GMT
Server: Apache/1.3.20-dev (Unix) PHP/4.0.7-dev
Last-Modified: Fri, 26 Jan 2001 06:08:38 GMT
ETag: "503d3-50-3a711466"
Accept-Ranges: bytes
Content-Length: 80
Keep-Alive: timeout=15, max=100
Connection: Keep-Alive
Content-Type: text/html