Function to find out if on Main Site?

Hi

I am using the global footer plugin. Working well :slight_smile:

I want to change the footer code so that only on the main site, it displays a certain bit of text in the footer.

I have found:

<?php if ( is_multisite() ) { echo 'Multisite is enabled'; } ?>

Does anyone here know if their is a function to determine if it is on the main site?

Can I put php code in the global footer admin box ?

Cheers

Johnny