JS: Vanilla Cross-Browser scroll position reporting

javascript.js

//https://stackoverflow.com/a/8028584
function getScrollPercent() {
  var h = document.documentElement,
  b = document.body,
  st = 'scrollTop',
  sh = 'scrollHeight';
  return (h[st]||b[st]) / ((h[sh]||b[sh]) - h.clientHeight) * 100;
}

document.addEventListener('scroll', function(){

    console.log( getScrollPercent() );

});