Transcript Nessun titolo diapositiva

Ministerial NEtwoRk for Valorising Activities in digitisation
WAI Initiative on accessibility
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Quality of a web site
The criteria for a quality cultural web
communication are based on two pillars:
Accessibility (WCAG/W3C)
Usability (ISO 9241-11) basic principles
The key concept of quality web site means to
pay attention to the users and their
requirements.
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Quality: definitions
(1)
Usability:
«The capability of the software product to enable
specified users to achieve specified goals with
effectiveness, productivity, safety and satisfaction
in specified contexts of use.»
(ISO/IEC 9126-1:1992)
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Quality: definitions
(2)
Accessibility:
«A Web site is considered to be accessible when
the informational content, navigational modes and
all the interactive features present are accessible
to all users, regardless of disabilities and
independently of technology used to access the
site and of the context in which they are working
whilst accessing the site»
(ISO TS 16071:2002)
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Web for Everyone
Accessibility:
«The power of the Web is in its universality.
Access by everyone regardless of disability is an
essential aspect»
Web for Everyone
available to all people, whatever their hardware,
software, network infrastructure, native language,
culture, geographical location, or physical or
mental ability
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Dimensions of accessibility
Connecting time
Availability
Compatibility of browser
Accessibility of disabilities
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Elements of connection
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Context of users
Many users may be operating in contexts
very different from your own :
They may not be able to see, hear, move
They may have difficulty reading or
comprehending text.
They may not have or be able to use a keyboard
or mouse.
They may have a text-only screen, a small screen,
or a slow Internet connection.
They may not speak or understand fluently the
language in which the document is written.
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Context of users
(cont.)
They may be in a situation where their eyes, ears,
or hands are busy or interfered with (e.g., driving
to work, working in a loud environment, etc.).
They may have an early version of a browser, a
different browser entirely, a voice browser, or a
different operating system.
Content developers must consider these
different situations during page design
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Definition of disability
The WHO World Health Organisation in 2001:
refers to “human functions” in general and not
simply to disability.
Moves away from the consequences of a
“disfunction” to components of “health”,
grouping them together under the heading of
“health domain”
Participation, not exclusion
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Different disabilities
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How do disabled people use the Web?
Throught “enabling” technology. This can be
hardware or software which:
effect “equivalent” conversion of the information
from one sense organ to another. Some examples
are:
from the computer monitor (sight) to touch
(Braille bar for visually-impaired users),
from the computer monitor (sight) to sound
(vocal synthesis for visually-impaired users),
from sound (audio documents) to sight (text documents)
(vocal recognition for motor-disabled and deaf users);
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How do disabled people use the Web?
(2)
permit different ways of using certain tools, for
example:
special mouse (for motor-disabled);
special keyboard (for motor-disabled);
compensate for disability of a sensory faculty, for example:
enlarging the text on the computer monitor (for
the
visually impaired)
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How do disabled people use the Web?
(3)
Specific tools are available to compensate
for other types of disability :
for users with difficulty in distinguishing colours
for users affected by photosensitive epilepsy
for users with learning difficulties or language
difficulties
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Advantages
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Web Accessibility Initiative
The World Wide Web Consortium (W3C) has
promoted the Web Accessibility Initiative
(WAI).
The objective is to produce strategies,
guidelines, resources to make the Web
accessible to people with disabilities
http://www.w3.org/WAI/
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Web Accessibility Initiative
 WAI deals with Web accessibility in the lay sense;
that is, not only as far as regards contents, but also
in terms of the tools used to realise the Web pages,
the browser and, more generically, technologies for
Web access.
 Accessibility is a process involving many actors
(people, developers, user agents). Hence:
 WCAG
 ATAG
 UAAG
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Web Content Accessibility Guidelines
were developed by the Web Content
Accessibility Guidelines Working Group
(WCAG WG);
became a W3C Recommendation 5 May 1999;
explain how to make accessible Web sites;
contain general guidelines;
have three priority levels of normative
checkpoints;
have extensive supporting resources
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Web Content Accessibility Guidelines (2)
It explains how to make Web content
accessible to people with disabilities. Web
"content" generally refers to the information
in a Web page or Web application, including
text, images, forms, sounds, and such.
WCAG 1.0 has 14 guidelines that are general
principles of accessible design. Each
guideline has one or more checkpoints that
explain how the guideline applies in a
specific area (65 in total).
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Resources for WCAG
 There are extensive implementation support
resources for WCAG 1.0, including:
 WCAG 1.0 Checklist
 WCAG 1.0 Techniques
 WCAG 1.0 Frequently Asked Questions (FAQ)
WCAG 1.0 Conformance Logos
 WCAG 1.0 Translations
WCAG 1.0 Fact Sheet
 WCAG 1.0 Curriculum
 QuickTips for Accessible Web Sites
 Evaluating Web Sites for Accessibility
 Implementation Planning for Web Accessibility
 Planning Web Accessibility Training
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WCAG 1.0: conformance level
Three priorities:
Priority 1 (A-compliant):
Criteria a web developer must satisfy
Basic requirement for some groups to be able to access
web documents
Priority 2 (AA-compliant):
Criteria a web developer should satisfy
Removes significant barriers to accessing web
documents
Priority 3 (AAA-compliant):
Criteria a web developer may satisfy
Improves access to web documents
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WCAG 1.0: Level of conformance
Level A:
all priority 1 checkpoints are
satisfied
Level AA:
all priority 1 and 2 checkpoints
are satisfied
Level AAA:
all priority 1, 2 and 3
checkpoints are satisfied
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Synthesis of WCAG 1.0 guidelines
1. Provide equivalent alternatives to auditory and visual content.
Non-text element includes: images, graphical representations of text
(including symbols), image map region
2. Don't rely on color alone.
Ensure that all information conveyed with color is also available
without color.
3. Use markup and style sheets and do so properly.
Use style sheets to control layout and presentation. Use relative
rather than absolute units in markup language attribute values and
style sheet property values.
4. Clarify natural language usage.
Clearly identify changes in the natural language of a document's
text and any text equivalents
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Synthesis of WCAG 1.0 guidelines
(cont.)
5. Create tables that transform gracefully.
Ensure that tables have necessary markup to
betransformed by accessible browsers and other user
agents.
6. Ensure that pages featuring new technologies
transform gracefully.
Ensure that pagesare accessible even when newer
technologies are not supported or are turned off.
7. Ensure user control of time-sensitive content
changes.
Ensure that moving, blinking, scrolling, or auto-updating
objects or pages may be paused or stopped.
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Synthesis of WCAG 1.0 guidelines
(cont.)
8. Ensure direct accessibility of embedded user interfaces
Ensure that the user interface follows principles of accessible
design: device-independent access to functionality, keyboard
operability, self-voicing, etc.
9. Design for device-independence
Use features that enable activation of page elements via a variety of
input devices.
10.Use interim solutions so that assistive technologies and older
browsers will operate correctly.
11.Use W3C technologies and guidelines according to
specification.
Where it is not possible to use a W3C technology, or doing so
results in material that does not transform gracefully, provide an
alternative version of the content that is accessible.
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Synthesis of WCAG 1.0 guidelines
(cont.)
12. Provide context and orientation information.
Provide context and orientation information to help
users understand complex pages or elements.
13. Provide clear navigation mechanisms.
Provide clear and consistent navigation mechanisms -orientation information, navigation bars, a site map, etc.
-- to increase the likelihood that a person will find what
they are looking for at a site.
14. Ensure that documents are clear and simple so they
may be more easily understood.
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Example 1: images
 Provide a text equivalent for every non-text element
 (e.g. via «alt», «longdesc», or in element content)
 This includes:
Images
graphical representations of text (including symbols)
image map regions
animations (e.g., animated GIFs)
applets and programmatic objects
ascii art, frames, scripts, images used as list bullets, spacers,
graphical buttons
sounds (played with or without user interaction)
stand-alone audio files, audio tracks of video, and video.
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Example 1: images
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Example 1: images
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Example 2: color
Ensure that foreground and background
color combinations provide sufficient
contrast when viewed by someone having
color deficits or when viewed on a black and
white screen.
[Priority 2 for images, Priority 3 for text]
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Example 3: multimedia
Until user agents can automatically read
aloud the text equivalent of a visual track,
provide an auditory description of the
important information of the visual track of a
multimedia presentation.
[Priority 1]
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Exemple 4: code validation
Create documents that validate to published
formal grammars.
Use for example W3C validator.
Important show DOCTYPE.
[Priority 2]
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Example 5: relative units
Use relative units (% or em) rather than
absolute units in:
markup language attribute values
style sheet property values
[Priority 2]
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Example 6: metadata
 Provide metadata to add semantic information to
pages and sites.
For example, use DUBLIN CORE to indicate the
 Document author
(<meta name="DC.Creator" content="Oreste Signore" /> )
 Content type
(<meta name="DC.Subject" content= “islamic art" /> )
 etc.
[Priority 2]
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WCAG 2.0: principle 1
Content must be perceivable.
Provide text alternatives for all non-text content
Provide synchronized alternatives for multimedia
Ensure that information and structure can be
separated from presentation
Make it easy to distinguish foreground
information from its background
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WCAG 2.0: principle 2
 Interface components in the content must be
operable.
 Make all functionality operable via a keyboard interface
 Allow users to control time limits on their reading or
interaction
 Allow users to avoid content that could cause seizures due
to photosensitivity
 Provide mechanisms to help users find content, orient
themselves within it, and navigate through it
 Help users avoid mistakes and make it easy to correct
mistakes that do occur
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WCAG 2.0: principle 3
Content and controls must be
understandable.
Make text content readable and understandable.
Make the placement and functionality of content
predictable.
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WCAG 2.0: principle 4
Content should be robust enough to work
with current and future user agents
(including assistive technologies)
Support compatibility with current and future user
agents (including assistive technologies)
Ensure that content is accessible or provide an
accessible alternative
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WCAG 2.0: some concepts
Baseline
The set of technologies that an author assumes
are supported and turned on in accessible user
agents
Conformance
A and AA for minimum or enhanced accessibility
level
 AAA achieves additional accessibility
enhancements
AAA requires that at least 50% of level 3 success
criteria are satisfied
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WCAG 1.0 vs WCAG 2.0
WCAG 2.0 applicable to a variety of
situations and technologies, including those
that not yet exist
Checkpoints in WCAG 1.0 seemed to be of
different importance (priority level)
All WCAG 2.0 success criteria are essential
for some people
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Thank you for your attention!
 Questions?
 References
 utilityLinks.html
 http://www.minervaeurope.org
 http://www.minervaeurope.org
/MEDCULT/home.html
 Oreste Signore
 [email protected]
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