The common extension for an Include file in an Active Server Page is .INC. However, the included page, like the main page, may contain code that you don’t want to share with the world. If you use the .INC extension, browsers can type the filename into the URL and pull out your source. A better way is to use the extension .ASP for Include files. If a Web surfer tries to view the file, the server will execute the included portion of the page without revealing the ASP code.