Using Server Side Includes - SSI

SSI works in conjunction with a web page usually with the .shtml extension.  

The .shtml extension tells the server to do something different with the web page. When you append the .html or .htm extension, this tells the server to "read" the page only. 

The .shtml extension tells the server to "Execute" the page, in addition to just reading it.

So, why would you want to execute the page? 

There are various commands you can program into a web page, which the server will look for and parse when the file is called as .shtml. 

In many cases, this mode is used in conjunction with Server Side Include (SSI) tags, to call a CGI script. For example, you have a visitor counter script, and we'll call it count.cgi. Every time someone visits your website, you want the script to be called, so that it logs the visitor into a file.


To do this, you would place an SSI tag into your web page. The tag in this case, would look something like:

<!--#exec cgi="/cgi-bin/count.cgi" -->

This small tag, which is hidden in the html coding of your page is telling the server to:

1. Go to the cgi-bin
2. Execute count.cgi

That's it! The information has been captured and processed by the count.cgi script. Of course, that's the short version of what happens. The long version would no doubt, would take us far beyond the scope of this document.

PLEASE do not use the .shtml extension on "all" of your web pages unless it's absolutely necessary. 

With a busy web site, this means that every page must be executed, as opposed to just read. 

This as you can appreciate, can add considerable memory and CPU load to the system. 

As always, read the instructions that came with your script carefully.   They should provide specific instructions on how to configure the script, as well as the SSI tag.