Server Side Includes (SSI) is a list of directives that will permit you to include the content of a text file in an HTML file. In this manner, you'll be able to add some content to various web pages in your website and adjust it by just updating one text file. You'll be able to furthermore add the output of various scripts so that the current time and date, the IP address of the website visitor or the properties of some file show on your site. This will help you add some dynamic content to static webpages, making the website more inviting to your site visitors and creating a professional appearance. It will be quicker to revise this content as compared to editing every static page one at a time. If you wish to use Server Side Includes in your website, the pages that incorporate the content of any kind of file need to be with extension .shtml.