Server Side Includes (SSI) is a basic server-side language, which enables you to incorporate text from a specific source in a website. In the most typical scenario, the text from one file is incorporated in a different one, providing a website the feeling that it is dynamic. For instance, in case your website is comprised of ten pages, 5 of them can easily have the content of any kind of file, such as horoscope.txt. In case you change this text file, the updated content will come up on all of the five webpages, which shall enable you to revise your site much easier than if you had to update a component of all 5 pages. Server Side Includes is in some cases utilized to include the output of basic commands, scripts or functions as well - a hit counter that is displayed on the website, the present date and time or the customer's IP address. Every webpage that uses SSI should have a special extension - .shtml.