James Graham On 09-06-04 13.11:
Joshue O Connor wrote:
On Wed, 3 Jun 2009, Ian Hickson wrote:
Is the need not served by <caption>?
No. A caption is provided visually. [...]
It is also worth noting that <caption> is a terse descriptor. @summary
is a long descriptor.
Since this is clearly going to be a long discussion it might help (and
would certainly help me) if we start from clear premises. So it would be
great if statements like "<caption> is..." could be clear about whether
they are referring to spec requirements, actual author practice, some
sort of best practice (that may or may not match actual common
practice), or something else, along with pointer to the relevant
documentation/evidence.
In this case I can't see anything in a HTML spec to back up your claim
that <caption> must be terse whilst @summary must be long.
HTML 4.01 on @summary (versus <caption>):
[1][2]: "summary [...] purpose/structure for speech output"
[3]: "Each table may have an associated caption (see the CAPTION
element) that provides a short description of the table's purpose.
A longer description may also be provided (via the summary
attribute) for the benefit of people using speech or Braille-based
user agents."
[4]: "summary = text [CS]
This attribute provides a summary of the table's purpose and
structure for user agents rendering to non-visual media such as
speech and Braille."
[4]: "The following informative list describes what operations
user agents may carry out when rendering a table: Make the table
summary available to the user. Authors should provide a summary of
a table's content and structure so that people using non-visual
user agents may better understand it."
[5]: "When present, the CAPTION element's text should describe the
nature of the table.[...]
Visual user agents allow sighted people to quickly grasp the
structure of the table from the headings as well as the caption. A
consequence of this is that captions will often be inadequate as a
summary of the purpose and structure of the table from the
perspective of people relying on non-visual user agents.
Authors should therefore take care to provide additional
information summarizing the purpose and structure of the table
using the summary attribute of the TABLE element. This is
especially important for tables without captions. Examples below
illustrate the use of the summary attribute."
[6]: "summary of table contents"
[6]: "table [...] summary of contents"
[7]: "Section A.1.3 (previously A.3)
The longdesc attribute was said to be specified for tables. It is
not. Instead, the summary attribute allows authors to give longer
descriptions of tables."
[7]: "A.3.3 Changes for accessibility [...]
Authors may provide long descriptions of tables (see the summary
attribute), images and frames (see the longdesc attribute)."
In general it
seems problematic to require that caption be terse because certain types
of documents inherently have long table captions; scientific papers
often put a paragraph or more of text in the table caption explaining
how to read the table, for example.
HTML 5 has the <figure> element, which has its own caption
element. The need for "caption groups" (analogy to <hgroup>) could
eventually be served by e.g. placing a paragraph between the
figure caption and the table - for example.
[1] http://www.w3.org/TR/html4/index/attributes
[2] http://www.w3.org/TR/html4/sgml/dtd
[3] http://www.w3.org/TR/html4/struct/tables#h-11.1
[4] http://www.w3.org/TR/html4/struct/tables#h-11.2.1
[5] http://www.w3.org/TR/html4/struct/tables#h-11.2.2
[6] http://www.w3.org/TR/html4/index/list
[7] http://www.w3.org/TR/html4/appendix/changes
[8]
http://www.whatwg.org/specs/web-apps/current-work/multipage/tabular-data.html#the-caption-element
--
leif halvard silli
