HTML 5

3.6. The root element

3.6.1. The html element

Contexts in which this element may be used:

As the root element of a document.

Wherever a subdocument fragment is allowed in a compound document.

Content model:

A head element followed by a body element.

Element-specific attributes:

manifest

DOM interface:

No difference from HTMLElement.

The html element represents the root of an HTML document.

The manifest attribute gives the address of the document's application cache manifest, if there is one. If the attribute is present, the attribute's value must be a valid URI (or IRI).

The manifest attribute only has an effect during the early stages of document load. Changing the attribute dynamically thus has no effect (and thus, no DOM API is provided for this attribute). Furthermore, as it is processed before any base elements are seen, its value is not subject to being made relative to any base URI.

Though it has absolutely no effect and no meaning, the html element, in HTML documents, may have an xmlns attribute specified, if, and only if, it has the exact value "http://www.w3.org/1999/xhtml". This does not apply to XML documents.

In HTML, the xmlns attribute has absolutely no effect. It is basically a talisman. It is allowed merely to make migration to and from XHTML mildly easier. When parsed by an HTML parser, the attribute ends up in the null namespace, not the "http://www.w3.org/2000/xmlns/" namespace like namespace declaration attributes in XML do.

In XML, an xmlns attribute is part of the namespace declaration mechanism, and an element cannot actually have an xmlns attribute in the null namespace specified.