If your web server is configured to support them you can use server side includes (SSI).

<!--#include file="included.html" -->

>Lately I have been doing mostly ASP.NET pages where for a common header and a footer I use web user controls.
>
>If I want to create simple static .html pages but have a common header and a footer on all of them, how do you do it?
>
>Thank you in advance.