Server Side Includes (SSI) is actually a list of directives that will enable you to include the content of a text file inside an HTML file. In this way, you are able to add any kind of content to numerous pages on your website and modify it by just editing an individual text file. You'll be able to also add the output of different scripts so that the present date and time, the IP address of the visitor or the properties of a file show on your website. This will allow you to add some dynamic content to static webpages, making the website more desirable to your visitors and creating a far more professional overall appearance. It will also be simpler to update this content compared to updating each static page one at a time. If you want to use Server Side Includes in your site, the pages that contain the content of any kind of file must be with extension .shtml.