Server Side Includes (SSI) is a simple server-side language, which enables you to incorporate text from a specific source inside a website. In the most typical case, the text from one file is incorporated in a different one, providing a site the sense it is dynamic. For example, if your site involves ten pages, 5 of them can easily have the content of any kind of file, like horoscope.txt. If you ever change this text file, the new content will appear on all five webpages, which will let you update your website faster and easier than if you had to change a component of all 5 pages. Server Side Includes is occasionally employed to contain the output of basic commands, scripts or functions as well - a hit counter that is displayed on the site, the current time and date or the visitor's IP address. Any webpage that works by using SSI must have a particular extension - .shtml.