docs: function getRectangle(el){
                          var box = el.getBoundingClientRect(),
                              top = Math.round(box.top + window.pageYOffset),
                              left = Math.round(box.left + window.pageXOffset),
                              height = typeof el.offsetHeight === 'undefined' ? 0 : el.offsetHeight,
                              width = typeof el.offsetWidth === 'undefined' ? 0 : el.offsetWidth;
  
                          return { top: top, left: left, height: height, width: width, meanY: top + height / 2}
                      }