I just want some simple JQ/JS to check if the current page/window (not a particular element) has a vertical scrollbar.
Googling gives me stuff that seems overly comp
Simply compare the width of the documents root element (i.e. html element) against the inner portion of the window:
if ((window.innerWidth - document.documentElement.clientWidth) >0) console.log('V-scrollbar active')
If you also need to know the scrollbar width:
vScrollbarWidth = window.innerWidth - document.documentElement.clientWidth;