Includes

Use of server-side includes (SSI) makes a Web site simple to maintain. By simply calling a file containing the desired reusable code, hours of busywork are eliminated.

On our IIS servers, the file in which you call the include files must have an .asp extension. It is strongly advised that your include files also have an .asp extension to allow for future ASP enhancements.

Includes can point relative to the file:

<!--#include file="../_include/header.asp">

...or using the base directory of the web as a starting point:

<!--#include virtual="_include/header.asp">