The Document.prepend() method inserts a set of Node objects or string objects before the first child of the document. String objects are inserted as equivalent Text nodes.
This method prepends a child to a Document. To prepend to an arbitrary element in the tree, see Element.prepend().
prepend(param1)
prepend(param1, param2)
prepend(param1, param2, paramN)
If you try to prepend 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.prepend(html);
If you are creating a new document without any existing element, you can prepend a root HTML element (or a root SVG element):
let doc = new Document();
let html = document.createElement("html");
doc.prepend(html);
doc.children;