The DocumentType.replaceWith() method replaces the document type with a set of given nodes.
replaceWith(node1)
replaceWith(node1, node2)
replaceWith(node1, node2, /* …, */ nodeN)node1, …, nodeNA set of nodes to replace the DocumentType with.
None (undefined).
HierarchyRequestError DOMExceptionThrown when the node cannot be inserted at the specified point in the hierarchy.
replaceWith()let svgDt = document.implementation.createDocumentType(
"svg:svg",
"-//W3C//DTD SVG 1.1//EN",
"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd",
);
document.doctype.replaceWith(svgDt);