Server Side Includes (SSI) is a popular server-side scripting language, which is used to include the content of one file inside another file. It's employed mostly with online content and it can help to make a static HTML website far more dynamic. If you want to have a daily quote shown on a number of pages on your website, as an example, you can create a text file and replace the quote in it every single day. All the web pages in which this file is incorporated are going to display the updated quote, so you will not have to edit all of them manually every single time. SSI could also be used to incorporate the output of simple functions as opposed to a static file - for instance, the viewer's IP address, a hit counter or the current time and date. By doing this, you may make your site appear far more professional and more attractive to the website visitors. Pages that implement SSI have a .shtml extension.