When the user enters the URL "http://bpastudio.csudh.edu/articles/hoho.htm" into the Web browser and hits the Enter key, the client first establishes a connection to the Web server program running on the host bpastudio.csudh.edu. It then sends the following message:
GET /articles/hoho.htm HTTP/1.0 Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-powerpoint, application/vnd.ms-excel, application/msword, */* Accept-Language: ko,en-us;q=0.5 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0) Host: bpastudio.csudh.edu Proxy-Connection: Keep-Alive
The keywords and format of this message are defined by the HTTP protocol. (Yes, Tim Berners-Lee just made them up). The message says that the client wishes to retrieve a document called hoho.htm from the Web site's articles subdirectory. It also gives certain characteristics of the client like the operating system it is running (Windows NT 5.0), the data types it can display (gif, jpeg, msword, etc.), the character sets it can display (US English and Korean), and the Web client software it is running (MSIE 5.5).