The Document.append() method inserts a set of Node objects or strings after the last child of the document. Strings are inserted as equivalent Text nodes.
This method appends a child to a Document. To append to an arbitrary element in the tree, see Element.append().
append(param1)
append(param1, param2)
append(param1, param2, /* …, */ paramN)param1, …, paramNA set of Node objects or strings to insert.
None (undefined).
HierarchyRequestError DOMExceptionThrown when the node cannot be inserted at the specified point in the hierarchy.
If you try to append an element to an existing HTML document, it might throw a HierarchyRequestError DOMException given a <html> element already exists.
let html = document.createElement("html");
document.append(html);
// HierarchyRequestError: The operation would yield an incorrect node tree.If you are creating a new document without any existing element, you can append a root HTML element (or a root SVG element):
let doc = new Document();
let html = document.createElement("html");
doc.append(html);
doc.children; // HTMLCollection [<html>]