Server Side Includes (SSI) is a simple server-side language, which enables you to include text from a specific source inside a website. In the most popular case, the text from a single file is integrated in a different one, giving a site the sense that it's dynamic. For example, in case your site includes ten pages, 5 of them can easily include the content of any kind of file, such as horoscope.txt. As soon as you alter this text file, the modified content will appear on all five webpages, which will permit you to revise your site faster and easier than if you had to change part of all five web pages. Server Side Includes is occasionally used to include the output of basic commands, scripts or functions as well - a hit counter that is displayed on the site, the present time and date or the visitor's IP address. Every web page that uses SSI will need to have a particular extension - .shtml.
