Server Side Includes (SSI) is a widely used server-side scripting language, which is used to add the content of one file inside another file. It's utilized mainly with online content and it could make a static HTML website a lot more dynamic. If you want to have a daily quote displayed on several web pages of your site, for example, you can create a text file and replace the quote in it each day. All web pages where this file is integrated will show the updated quote, so you will not have to update all of them by hand every single time. SSI may also be used to incorporate the output of simple functions instead of a static file - for example, the client's IP address, a hit counter or perhaps the current time and date. In this way, you may make your website look more professional and more appealing to the site visitors. Pages that implement SSI have a .shtml extension.