[N9ne]

I'm not sure it's possible on an index.html, but if you rename it to index.php, you can use the following (not tested - will not support - this is off the top of my head) :

PHP Code:

<?php
require("forum/global.php");
echo "$header";
?>

<!-- Do whatever else you want here with html -->

<?php
echo "$footer";
?>

I doubt that will work straight off, but I'm sure with some modification keeping the same base it will work.