Server Side Includes (SSI) is a popular server-side scripting language, which can be used to include the content of one file inside another file. It's employed mostly with online content and it can help make a static HTML website more dynamic. If you'd like to have a daily quote displayed on multiple webpages within your website, as an example, you can make a text file and switch the quote inside it daily. All of the webpages where this file is incorporated will show the modified quote, so you will not have to change them personally every time. SSI can also be used to contain the output of simple functions rather than a static file - for instance, the visitor's IP address, a hit counter or even the present time and date. By doing this, you can make your website appear a lot more professional and a lot more attractive to the site visitors. Pages that use SSI get a .shtml extension.