1. What are Server Side Includes?|
2. Do I need Server Side Includes to run this?
Server Side Includes allow for your server to parse your html pages and return certain things in place of your server side include calls.
Server Side Includes allow you to imbed special tags in order for your server to parse this document and replace these tags with the information you requested to beplaced there, whether it be a CGI script, command, or even an environment variable. This all occurs on the server side, which means that when the document reaches the end user, they won't even know the server side includes were ever used, and if they view source, they won't see any trace of them.
Matt Kruse's Server Side Includes Explanation
NCSA HTTPd Tutorial: Server Side Includes (SSI)
Apache module mod_include
No. To most easily implement this script you will need to have Server Side Includes turned on on your system. There are several utilities which allow you to get around the unfortunate problem that many users have: Server Side Includes turned off. Below is a list of some of the ways to get around this.
Sarang Gupta's fakessi.pl
A three line perl script which parses Server Side Include cgi directives and returns to the web browser the parsed web page. Kinda messy, but there just for an example.