Access dimensions and position of the first Element's content + padding + border + margin box in this list.
This returns a rectangle with the dimenions actually available for content
in this element, in pixels, regardless of this element's box-sizing
property. Unlike getBoundingClientRect
, the dimensions of this rectangle
will return the same numerical height if the element is hidden or not. This
can be used to retrieve jQuery's outerHeight
value for an element.