The tfoot element represents the block of rows that consist of the column summaries (footers) for its parent table element.
A tfoot element must have a start tag.
A tfoot element’s end tag may be omitted if the tfoot element is immediately followed by a tbody element, or if there is no more content in the parent element.
interface HTMLTableSectionElement : HTMLElement { readonly attribute HTMLCollection rows; HTMLElement insertRow(optional long index); void deleteRow(long index); };