Wordpress Multi site auto id

I have a set of sites set up on thier own domain (79 to be excatat)

I am using this JS in my code I can see that the sites are listed in the PIWIK wp plugin but how do i get the site ID into a variable so it will auto add on each themes JS when i create a new site going forward as this will make PIWIK really useful as it is an auto setup for the theme and only requires i add the JS one time in a child theme to always be there when a new site is created under wordpress multi site

If you are using Wordpress then use the WP-Piwik plugin which should do this automatically for you! WP-Piwik — WordPress Plugins