Server Side Includes (SSI) is a widely used server-side scripting language, employed to add the content of one file within a second file. It's employed mainly with online content and it will make a static HTML website a lot more dynamic. If you wish to have a daily quote displayed on many pages on your site, for example, you can create a text file and switch the quote inside it each day. All pages in which this file is incorporated will show the modified quote, so you will not have to modify all of them personally each time. SSI may also be used to include the output of simple functions rather than a static file - for example, the client's IP address, a hit counter or even the current date and time. In this manner, you may make your site seem much more professional and much more attractive to the visitors. Web pages that implement SSI have a .shtml extension.