Is there any way to use cookies with SSI?
 

The front page of my website sets a cookie to keep track of the CSS style the user prefers. It's easy to read and act upon that cookie using PHP, but I also need that style preference to apply to my more-or-less static pages, which at the moment just use SSI to include global header text.

Is there any way to use this cookie in SSI, or do I need to use PHP everywhere?

Take a look at:
http://www.w3.org/Jigsaw/Doc/User/SSI.html#cookie

The other option is to virtually include a perl or php script and read the cookies there.

I didn't know I could do that...