Server Side Includes allow you to write some commonly used code once and have the server insert it into the pages for you. They cut down your development time by more than 100% as you only need to make changes in the include file and it automatically gets updated in all the pages that use the include. Best of all it reduces our FTP time as you only need to FTP one file and not all the pages using the Include. They are a huge time savers. This guide describes what SSIs are, and how to use them.
This site presents complete SSI tutorials and reference pages covering everythyng from SSI basics to more advanced topics. Major topics include: Enabling SSI on Your Server, The ECHO Directive, The INCLUDE Directive, The EXEC and VIRTUAL Directives, Nested Directives, A Real Back Button, and eXtended SSI Directives.
This tutorial explains how to create documents which include other documents and various dynamically generated information, such as the current date, the file's last modification date, and the size or last modification of other files.