dfn-design-pattern: Difference between revisions
(One intermediate revision by one other user not shown) | |||
Line 50: | Line 50: | ||
===Assistive Technology=== | ===Assistive Technology=== | ||
The proposed dfn design pattern assumes that screen readers don't treat <code>dfn</code> as a special case like <code>abbr</code> or <code>acronym</code>. Is this actually the case? Please | The proposed dfn design pattern assumes that screen readers don't treat <code>dfn</code> as a special case like <code>abbr</code> or <code>acronym</code>. Is this actually the case? Please note results of testing on that item in the [[assistive-technology-abbr-results|assistive technology results]] page. | ||
===Usage in the wild=== | ===Usage in the wild=== | ||
Line 58: | Line 58: | ||
* [http://juicystudio.com/article/jargon-busting-with-the-definition-element.php Juicy Studios: Jargon Busting with the Definition Element] | * [http://juicystudio.com/article/jargon-busting-with-the-definition-element.php Juicy Studios: Jargon Busting with the Definition Element] | ||
* [http://alistapart.com/articles/hattrick A List Apart: The Accessibility Hat Trick: Getting Abbreviations Right] | * [http://alistapart.com/articles/hattrick A List Apart: The Accessibility Hat Trick: Getting Abbreviations Right] | ||
* [http://www.arthrogryposis.de/iga/iga-ev/schirmherr German Arthrogryposis Support Group] (medical terms checked against a glossary) | |||
* ... | * ... | ||
Latest revision as of 14:23, 14 January 2009
Dfn design pattern
Important: this is currently a proposal: it is not a finalised design pattern.
This page is intended for discussion and exploration of a design pattern to complement the abbr design pattern while addressing the abbr design pattern issues, particularly the accessibility issues.
Purpose
The abbr design pattern is used in several microformats to enclose standardised data such as the datetime design pattern in the title
attribute. However some assistive technology will expose this data directly to the user, which is often undesirable.
See also assistive technology abbr results.
This problem arises because the title
attribute has a different semantic meaning when it is attached to an abbr
or acronym
than it does on other elements. Usually the title
attribute is used to provide provide advisory information. But for abbr
or acronym
the title
is used to provide an expanded form of the text contained between the opening and closing tags. This is why the abbr
element was chosen to contain datetime information: the ISO format is an expanded form of the human-readable text contained within the element. Because screen readers can be configured to treat abbr
and acronym
elements as special cases, the title
attribute is sometimes read aloud.
Proposal
Rather than expand the abbr design pattern to any element (or to a semantically neutral element such as span
), it would be better to use an element that has semantic value but which isn't treated as a special case by assistive technology.
dfn
The dfn element indicates the defining instance of the enclosed term. This element is not widely used but where it used, it is often used in a similar way to the abbr
element. Although the title
is not required for the dfn
element, it is often used to provide expanded information.
The semantic meaning of dfn
, as it is currently used, is potentially similar enough to abbr
element to allow it to be used as an alternative:
<abbr class="dtstart" title="2007-08-16T22:00:00">10pm on August 16th</abbr> <dfn class="dtstart" title="2007-08-16T22:00:00">10pm on August 16th</dfn>
Issues
Semantics
The dfn
is not intended for definitions; it is intended for defining instances. Does this mean that it must always be used for the first instance of a term (such as a date)?
Is the dfn
element equally appropriate as the abbr
for information such as datetimes and geo or is this stretching the semantic meaning of the element beyond a reasonable limit?
HTML5
In HTML5, the element semantics have completely changed and would be incompatable with this pattern.
Parsers
Existing microformats parsers (such as the Operator extension to Firefox) would need to be updated to handle this proposed alternative to the abbr design pattern. However, this is true of any proposed alternatives.
Complexity
Microformats are intended to be easy to publish. The number of design patterns should be kept to a minimum. Every new design pattern is potentially a new barrier to entry for publishers.
Assistive Technology
The proposed dfn design pattern assumes that screen readers don't treat dfn
as a special case like abbr
or acronym
. Is this actually the case? Please note results of testing on that item in the assistive technology results page.
Usage in the wild
This design pattern is built on the assumption that, although the dfn
is not widely used, where it used, it is most often used in conjunction with the title
attribute. Please document examples and references here:
- Juicy Studios: Jargon Busting with the Definition Element
- A List Apart: The Accessibility Hat Trick: Getting Abbreviations Right
- German Arthrogryposis Support Group (medical terms checked against a glossary)
- ...
Alternatives
- title-trigger
- ...