DocumentType: name property

The read-only name property of the DocumentType returns the type of the document.

For synthetic DocumentType, this property reflects the value given in parameter to DOMImplementation.createDocumentType().

For HTML documents, browsers always set it up to html, whatever the actual DOCTYPE in the source code is.

const docType = document.implementation.createDocumentType("html", "", "");

console.log(docType.name); // Displays `html`