function getScroll()

in js/popper.js [304:317]


function getScroll(element) {
  var side = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 'top';

  var upperSide = side === 'top' ? 'scrollTop' : 'scrollLeft';
  var nodeName = element.nodeName;

  if (nodeName === 'BODY' || nodeName === 'HTML') {
    var html = element.ownerDocument.documentElement;
    var scrollingElement = element.ownerDocument.scrollingElement || html;
    return scrollingElement[upperSide];
  }

  return element[upperSide];
}