Documents are built from elements. These elements form a tree using
the DOM. Each element also has a predefined meaning, which is explained
in this section. User agent requirements for how to handle each element
are also given, along with rules for authors on how to use the element.
HTML documents do not exist in a vacuum — this section defines
many of the features that affect environments that deal with multiple
pages, links between pages, and running scripts.
The Editing APIs: HTML documents can provide a
number of mechanisms for users to modify content, which are described in
The Communication APIs: Applications written in
HTML often require mechanisms to communicate with remote servers, as well
as communicating with other applications from different domains running
on the same client.
All of these features would be for naught if they couldn't be
represented in a serialised form and sent to other people, and so this
section defines the syntax of HTML, along with rules for how to parse
This specification should be read like all other specifications. First,
it should be read cover-to-cover, multiple times. Then, it should be read
backwards at least once. Then it should be read by picking random sections
from the contents list and following all the cross-references.