Server Side Includes (SSI) is a range of directives that will enable you to include the content of a text file inside an HTML file. In this way, you'll be able to add any kind of content to few different web pages on your website and alter it just by editing one text file. You're able to also add the output of different scripts so the current time and date, the IP address of the website visitor or the attributes of a file show on your site. This shall allow you to add some dynamic content to static web pages, making the website more appealing to your website visitors and creating a much more professional overall look. It will be much easier to revise this content when compared with updating every static web page one by one. If you want to use Server Side Includes on your site, the pages that include the content of any kind of file must be with extension .shtml.