How do I add SSI to my page?
Add the desired server side includes to the page, and then rename the page with a ".shtml" extension.
For an alternative, see below.
I want pages with a .html or other extension checked for SSI.
Create, if necessary, a file named ".htaccess" in the directory containing the pages. Add the following line to the file:
AddHandler server-parsed .html
".html" can be replaced with the desired filename extension.