title: How can I get the scrollbar position with JavaScript?
body: <p>I'm trying to detect the position of the browser's scrollbar with JavaScript to decide where in the page the current view is.</p>
  <p>My guess is that I have to detect where the thumb on the track is, and then the height of the thumb as a percentage of the total height of the track. Am I over-complicating it, or does JavaScript offer an easier solution than that? What would some code look like?</p>