Server Side Includes (SSI) allow a webmaster to include dynamic content from the server in the site's web pages. This can be as simple as information about when the current web page was last modified, to starting a program or displaying a file. This allows the server to adapt it's output and content to the user's actions.
The directives are executed on the server and only their result, if any, is sent to the client. This allows the server to display what is called 'dynamic content' without relying on the client browser's capabilities. An SSI based function will work regardless of whether the client web browser supports java, javascript, or other functions.
However, SSI has it's some security concerns associated with it. For this reason, it is not enabled by default on most servers. Since the server executes directives essentially at the request of the user, you are giving the user the ability to control the server in (hopefully) a limited fashion. Always consider carefully before enabling SSI.
SERVER SIDE INCLUDE TUTORIALS
- Configuring the Server
- Understanding Environment Variables
- Server
- Client
- SSI Directives
- SSI Cheatsheet