I have a website that runs fully on PHP. The footer is contained in footer.php. Is there a way to make the footer customizable via Wordpress?

Yes, you should be able to add widgets to your footer, if your theme is designed properly.

Additionally, you should be able to change the.css for your footer as well.

Hi,

Thanks for answering. I really don't know how to phrase this and might have supplied insufficient information. Let me try again.

Let's say I have a static page and want to modify its footer using Wordpress. The page and entire site is not actually built on Wordpress. It is purely PHP, HTML. I just want the footer to be customizable and installed Wordpress on a subdomain to be accessed in the backend. Its like I am marking the footer as Wordpress post that can be customized.

Can this be done? Thanks. :)

I can see a workaround ;)
so you just want the footer to come from wordpress (installed on a subdomain/or separate domain).

Here's what can be done
1) Add a page template into your wordpress theme which just includes footer, no header, no content no nothing :)
something like

<?php
/**
 * Template Name: Only footer
 * Description: A Page Template that display only footer content
 *
 */
 ?>
<?php get_footer('custom'); ?>

the problem with get_footer without parameter would be that it wont load any css. so then

2) define a footer-custom.php file in your theme, which has everything from footer.php, additionally it also loads css files .... <link rel="stylsheet" src="wp.mydomain.com.....">

3) Now create a new page in wp-admin and assign it the new page template 'Only footer'. Save the page and take down its permalink. eg: http://wp.mydomain.com/show-only-footer

4)Now go to your main website, find a suitable place where you want the wordpress footer to appear. and just do..

<?php
echo file_get_contents('http://wp.mydomain.com/show-only-footer');
?>

So lets say if you have added a 'recent-posts' widget in your footer throug wp-admin then a list of recent posts(links) shows up in the footer of your main non-wp site.

That should work!
Makes sense?