headelement followed by a
html element represents the root of
an HTML document.
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).
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
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 "
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
xmlns attribute in the null namespace specified.