The header element represents the header of a section.
flow content
global attributes & common.attrs.aria.implicit.region or common.attrs.aria.landmark.banner
A header element must have both a start tag and an end tag.
any element that can contain flow elements
The header element typically contains the headings for a section (an h1-h6 element or hgroup element), along with content such as introductory material or navigational aids for the section.
Uses HTMLElement.