There are a few things you might want to know if you’re looking to change the document type (doctype) using jQuery or Javascript. First, doctype is listed as a property in the W3C documentation, and is defined as read-only:
interface Document : Node {
readonly attribute DocumentType doctype;
readonly attribute DOMImplementation implementation;
readonly attribute Element documentElement;
Element createElement(in DOMString tagName)
raises(DOMException);
DocumentFragment createDocumentFragment();
While it may be possible to insert a doctype with javascript / jquery above the HTML tag, it is not advisable to do so. Sample code which would do this might look like:
