The content of most web pages can be divided into two categories: the variable content that changes from page to page and the static content that remains the same on every page.
The use of Server Side Include (SSI) is an effective way to maintain the static portions of a website. Changing a FAX number or adding the navigation to a new page is done in one "included" file and it automatically appears on every page of the website.
Web sites are a lot easier to build than they are to maintain. When your site gets to be bigger than a few pages, making changes to it can become a major time drain. There is however a simple technique you can use to make site maintenance easier. Server Side Include (SSI) is a server based technology that lets you build your web pages through a series of reusable components. The basic concepts of SSI are relatively simple.
<!--#include file="navbar.inc" -->
The web server automatically replaces the SSI directives with the content of the included files. Visitors to your website only see the merged pages, they don't even know the SSI was ever used.
While it is true that Server Side Include is a great way to manage this repetitive code, standard Server Side Processing brings with it a variety of disadvantages that might outweigh its usefulness.
MySSI solves these problems by "emulating" a web server without "running" a web server. All of your editing and viewing is performed on complete, properly formatted, HTML files. The MySSI process is only used to copy the changes made to the static portions of one HTML file to the other files in the website. The way this is done will become evident as we get into the demo.