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virtual

The value is a (%-encoded) URL-path. The URL cannot contain a scheme or hostname, only a path and an optional query string. If it does not begin with a slash (/) then it is taken to be relative to the current document.

A URL is constructed from the attribute, and the output the server would return if the URL were accessed by the client is included in the parsed output. Thus included files can be nested.

If the specified URL is a CGI program, the program will be executed and its output inserted in place of the directive in the parsed file. You may include a query string in a CGI url:

<!--#include virtual="/cgi-bin/example.cgi?argument=value" -->

include virtual should be used in preference to exec cgi to include the output of CGI programs into an HTML document.

If the KeptBodySize directive is correctly configured and valid for this included file, attempts to POST requests to the enclosing HTML document will be passed through to subrequests as POST requests as well. Without the directive, all subrequests are processed as GET requests.