[whatwg] Clarify how to indicate document hierarchy

[Benjamin Hawkes-Lewis]

Some web documents are standalone, but many if not most belong to a
hierarchy of documents. 

There has long been confusion about the correct way to indicate the
document hierarchy from within a given document. How should <title>
elements be written? How should site logos be marked up? Should <hX>
elements be used to indicate the structure of an individual page, or
also include titles from further up in the document hierarchy? Is such
markup superfluous to typed <link>s?

Differing views can be found at, for example:

SimpleBits quiz: http://tinyurl.com/create.php 

After text fallbacks, heading elements are arguably the single most
important accessibility feature HTML offers. They allow assistive
technology users to jump between sections of a document, rather than
being forced to listen to or read the entire stream.

WHATWG's specifications should establish clear guidelines about how
document hierarchy can be indicated. The web is a big place; its users
deserve consistent and efficient answers to the fundamental question of:
"Where am I?"

Some suggestions for further discussion follow.

<title>
=======

WHATWG should give two pieces of guidance for when a <title> is used to
indicate a document's place within a hierarchy of documents:

1) Unit titles should be listed from least to greatest (e.g. "Chapter 15
— Charles Dickens, Great Expectations — The Virtual Library" not "The
Virtual Library — Charles Dickens, Great Expectations — Chapter 15").
This seems to be the most convenient form when interacting with web
content as a stream, since it puts the information that changes most
frequently at the beginning. Compare how the titles of windows are
arranged in desktop environments.

2) Unit titles should be separated by sane punctuation that does not
impair aural or tactile accessibility, e.g. in English an em dash not
guillemots. Ideally, WHATWG could suggest punctuation for different
languages.

<link>
======

"Interactive user agents should provide users with a means to follow the
hyperlinks created using the link element, somewhere within their user
interface."

Since "Where am I?" is a fundamental question, and since this has
already been implemented in many user agents, this should be a MUST not
a SHOULD.

<h1> - <h6> and <header>
========================

I think the current draft is much less clear here. <h1> to <h6> are said
to "define headers for their sections". Should this, or should it not,
include headers for larger document units that the document happens to
be part of?

If it should, how can document mappers, especially those used by
assistive technology, distinguish the important local headers from more
general headers (such as site logos). And if there is a way for them to
distinguish such headers, how should they treat legacy content? 

If it should not, the specification needs to state this, given the past
history of people sometimes (counter-productively IMHO) using <h1> for
the site header on sub-pages.

--
Benjamin Hawkes-Lewis