Access dimensions and position of the Elements in this list.
Setting the height or width properties will set the height or width property for all elements in the 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. Getting the height or width returns the height or width of the first Element in this list.
getBoundingClientRect, the dimensions of this rectangle
will return the same numerical height if the element is hidden or not.