Server Side Includes (SSI) is a popular server-side scripting language, which is often used to add the content of one file inside of a second file. It's used principally with online content and it could help make a static HTML site a lot more dynamic. If you want to have a daily quote displayed on a variety of web pages on your website, as an example, you can make a text file and replace the quote within it each day. All the pages in which this file is included are going to display the updated quote, so you will not have to edit them personally every time. SSI can also be used to incorporate the output of basic functions rather than a static file - for example, the visitor's IP address, a hit counter or the present time and date. This way, you can make your website look much more professional and a lot more appealing to the visitors. Pages that employ SSI get a .shtml extension.