CGI environment vars for browser ID, etc.

Ann Lynnworth (
Fri, 5 May 1995 19:21:37 +0500

To answer Elisabeth's question about identifying the browser --

A CGI program has access to a great number of environment variables which
give you all sorts of information about what's happening at run time. This
is not available to plain HTML; you need to have a CGI program.

But if you do, here are some of the benefits:

' [CGI] <== The standard CGI variables
' CGI Version= The version of CGI spoken by the server
' Request Protocol= The server's info protocol (e.g. HTTP/1.0)
' Request Method= The method specified in the request (e.g., "GET")
' Executable Path= Physical pathname of the back-end (this program)
' Logical Path= Extra path info in logical space
' Physical Path= Extra path info in local physical space
' Query String= String following the "?" in the request URL
' Content Type= MIME content type of info supplied with request
' Content Length= Length, bytes, of info supplied with request
' Server Software= Version/revision of the info (HTTP) server
' Server Name= Server's network hostname (or alias from config)
' Server Port= Server's network port number
' Server Admin= E-Mail address of server's admin. (config)
' Referer= URL of referring document (HTTP/1.0 draft 12/94)
' From= E-Mail of client user (HTTP/1.0 draft 12/94)
' Remote Host= Remote client's network hostname
' Remote Address= Remote client's network address
' Authenticated Username=Username if present in request
' Authenticated Password=Password if present in request
' Authentication Method=Method used for authentication (e.g., "Basic")
' Authentication Realm=Name of realm for users/groups

If you're developing on a Windows NT platform, you might check out for more information. O'Reilly's server makes it
very easy to get at these facts.

Hope this helps,

Ann Lynnworth
Infobahn Construction Seminar --
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