Server Side Includes (SSI) are a method of integrating directives or commands into
HTML documents. The directives should be placed inside an HTML comment field. When a client asks a properly configured
Web server to send it a document that contains Server Side Includes, the Web server processes the directives and includes their output in what is sent to the client.
Two brief examples:
#include virtual="standard-page-footer.html"
#exec cgi="generate-page-footer.pl"