Server Side Include is a type of HTML comment that directs the web server to dynamically generated data.
It applied to an HTML document, provide for interactive real-time features such as echoing current time, conditional execution based on logical comparisons (if, else if, else), executing CGIs, etc.
Server Side Include tags can be added to a page where ever dynamic data is required and the server will process the command(s) within the tag(s) before the page is sent to the viewer of the page. An SSI tag will follow the format below:
Including a header/footer:
Including output from a CGI:
Including output from a SHELL command:
Output HTTP Environment Variables: