How to add header and footer with .htaccess

[Useless]

PHP seems the simplest way. Construct your html pages as you normally would but name each one whatever.php instead of whatever.html. On each php page, you'll place an include tag on top for your header like this:
<?php
include("header.html");
?>
At the bottom, where you want your footer to be, you'll place this:
<?php
include("footer.html");
?>
Obviously, you'll need to build your header.html and footer.html pages.

So, whatever.php could look something like this:
<?php
include("header.html");
?>
<table><tr><td>All the wacky porn shit you want on your page.
</td></td></table>
<?php
include("footer.html");
?>

Play with this a bit and you will get hooked on it. You'll find yourself building pages that are almost all include tags, pulling in info from other php and html source pages. As long as you use the .php extension you can use the php include tags. Otherwise, it can all be html code.
Keep in mind, you have to test these php pages online, unless you have PHP on your home system.