code: function getContentRect( elem ) {
  
          var rect = elem.getBoundingClientRect(),
              props = getCss( elem, [
                  "borderTopWidth", "borderRightWidth", "borderBottomWidth", "borderLeftWidth",
                  "paddingTop", "paddingRight", "paddingBottom", "paddingLeft"
              ], { toFloat: true } );
  
          return {
              top: rect.top + props.paddingTop + props.borderTopWidth,
              right: rect.right - ( props.paddingRight + props.borderRightWidth ),
              bottom: rect.bottom - ( props.paddingBottom + props.borderBottomWidth ),
              left: rect.left + props.paddingLeft + props.borderLeftWidth
          };
      }
docs: Calculates the rect of the content-box. Similar to getBoundingClientRect, but excludes padding and borders - and
  is much slower.
  
  @param   {HTMLElement} elem
  @returns {ClientRect}