Server Side Includes (SSI) is a widely used server-side scripting language, used to add the content of one file inside of a second file. It is employed mostly with online content and it could help to make a static HTML site more dynamic. If you wish to have a daily quote shown on several pages of your site, for instance, you can create a text file and replace the quote within it every day. All the web pages in which this file is included will show the updated quote, so you'll not have to alter all of them by hand every time. SSI can also be used to contain the output of basic functions rather than a static file - for example, the viewer's IP address, a hit counter or the current date and time. In this way, you may make your site appear far more professional and more attractive to the visitors. Web pages that employ SSI get a .shtml extension.