Can Site Wide Custom code Access data set in my wix studio backend?

In wix studio, Can I set a variable in my backend that would be accessible in the site wide custom code ?

MY site wide custom code is handling an audio player that is persistent across pages(Doesn’t reload when a new page is loaded). I want the music played to change when the user clicks on a new title.

I tried setting up a local storage variable but It does not seem to be accessible from the site wide custom code.

It’s getting me crazy, I would take any advice

MY site wide custom code is handling an audio player that is persistent across pages(Doesn’t reload when a new page is loaded)

Where is this custom code located in your site structure?