The read-only ownerDocument property of the Node interface returns the top-level document object of the node.
A Document that is the top-level object in which all the child nodes are created.
If this property is used on a node that is itself a document, the value is null.
// Given a node "p", get the top-level HTML
// child of the document object
const d = p.ownerDocument;
const html = d.documentElement;