dev/Accesibilidad

Nota: Esta es una traducción de una página de la documentación para desarrolladores (Developer docs), que se considera particularmente importante, y que en su versión original se actualiza frecuentemente. Por ello, se le recomienda que revise la página original en idioma inglés: Accessibility.

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Esta página necesita actualizarse con la información existente en la documentación vigente/moderna/actualizada en el idioma inglés original para Moodle. Se le sugiere al lector que consulte la página original en idioma inglés cuyo enlace está al fondo de esta página. y que, por favor, actualice esta información y quite la plantilla {{Actualizar}} cuando haya terminado.     (otras páginas pendientes de actualizar)

Nota del traductor: Esta documentación es la traducción de la página sobre accesabilidad de la documentación en inglés para desarrolladores. Si Usted quiere ver la información para usuarios sobre accesabilidad vea Accesibilidad.

Accesibilidad: Documentación para desarrolladores

Nota: Esta es una traducción de una página de la documentación para desarrolladores (Developer docs), que se considera particularmente importante, y que en su versión original se actualiza frecuentemente. Por ello, se le recomienda que revise la página original en idioma inglés: Accessibility.

Los sitios Web construidos con accesibilidad en mente son flexibles para cumplir las diferentes necesidades de los usuarios, sus preferencias y situaciones. A pesar de que estos métodos pueden aumentar la usabilidad para todos los usuarios de la Web, a menudo es requerido legalmente que se implementen en un esfuerzo específico para prevenir la discriminación en contra de personas con discapacidades.

Puntos de arranque

These are some readable introductions to accessibility that cover; what accessibility is, why it is important, as well as practical advice.

• Web Accessibility Initiative's Introduction to Web Accessibility
• Mark Pilgrim's Dive into Accessibility
• Joe Clark's Building Accessible Websites book

Moodle Accessibility Collaboration Group

To improve the accessibility and usability of Moodle, we have established this collaboration group to work together with Moodle developers, accessibility experts, administrators, IT professionals, and other interested entities and individuals. We welcome anyone who is interested in improving the accessibility of Moodle to join this group. You don’t need to be a technical guru or accessibility expert to join; however, it is expected that you are familiar with the basics of accessibility and are willing to dedicate a few hours each month to this collaboration effort.

We meet once a month to discuss accessibility priorities, typically on the first Monday of each month.

Visit http://collaborate.athenpro.org/group/moodle to join the mailing list.

To review past meetings or to see up coming meetings visit http://collaborate.athenpro.org/group/moodle/teleconferences/

Moodle-related accessibility coding guidelines

Use CSS, but still use headings, strong and emphasis

It is generally a good idea to separate a document's content HTML from how it is presented using CSS. There are some tags that affect a document's presentation but also contribute to the structure and meaning of the content. These tags should remain in HTML. This includes heading tags

,

,

..., which are used to form the document's hierarchical structure, and and tags, which are used to add meaning to sections of text.

Avoid using background images for important information

Users of non-visual browsers cannot see images. They can read the alt tags of normal images, but background images are not presented like normal images.

Image alt and title attributes

• An alt attribute is required (even if empty) on all images.
• If a link is wrapping an <img>, the <img> does not need a title attribute if the link has one.
• The alt for an image and the title for its surrounding link should usually differ. An image alt attribute provides a text equivalent to an image, whereas a title attribute adds supplementary information about the purpose or action associated with an image link. Simply repeating the same text in alt and title attributes adds little and can be annoying for screen reader users.

Links and buttons should be selectable and easily click-able

• An image used as an icon for a user to click should be large enough so that the user can click on it easily.
• Users should be able to navigate to all links and buttons using the keyboard.
• Generally we should avoid having two buttons/links that achieve the same action in the same area. This can be annoying and confusing for users of screen readers.

Support dynamic interaction with ARIA attributes

Events triggered by AJAX and JavaScript can be less obvious to users of non-visual browsers. ARIA attributes can assist users of such browsers to follow a dynamic change.

Use labels with inputs

Context can easily be lost without a visual presentation. Labels are needed on all input input elements (except button) to describe their purpose in a form. Labels should be unique on a page. Repeated elements should have a unique label that identifies the element within its context.

Use appropriate page titles

A page title is a starting point for a screen reader. Page titles should be unique and should make sense for the page. Avoid generic page titles.

All pages should be navigable using just a keyboard

It should be possible navigate to all points on a page just using a keyboard. Important events triggered by a mouse event should be able to be triggered when the item receives focus through keyboard navigation.

Avoid using colour alone to express meaning

Colour-blind users need additional information to gain meaning if colour is used as the emphasising feature. Also keep in mind that colours can have differing significance in different cultures, so colours should be configurable either through settings or language files.

Use sufficient color contrast when adding color to text. See Tracker ticket MDL 522391

https://tracker.moodle.org/browse/MDL-52391.

Role for button-type links

If a link acts as a button (not forwarding to another page, which is often the case when combined with Javascript), it should declare the role attribute button. Also, as a button is usually triggered by the Space bar, the Javascript should add proper event listeners on the link to accept this key. Read more at Mozilla Developer Network

Web standards, guidelines and legislation

International

• Web Accessibility Initiative
  • Web Content Accessibility Guidelines (WCAG)
  • Web Content Accessibility Guidelines 2.0 (draft)
    • An article on the problems with WCAG2 from A List Apart
  • Client-side scripting guidelines

• W3C ARIA

• WebAIM Form Accessibility guidelines
• WebAIM ARIA guidelines

USA

• Section 508

UK

• Equality Act 2010, in particular:
  • Section 20 - Duty to make adjustments
  • Section 29 - Provision of services, etc.
  • Schedule 25 - Information society services.

See also the Equality Act 2010 Statutory Code of Practice (PDF) for Services, public functions and associations.

• Public sector equality duty created by the Equality Act 2010.
• SENDA - Special Educational Needs and Disability Act/Bill
• Disability Discrimination Act 1995 (now merged ino the Equality Act 2010).
• BS 8878:2010 – 16 Steps for an accessible web product

Germany

• Barrierefreie Informationstechnik-Verordnung - BITV

France

• Référentiel Général d’Accessibilité des Administrations - RGAA

European Union

• Proposal for a Directive of the European Parliament and of the Council on the accessibility of public sector bodies' websites.

Tools

Firefox extensions

• Firefox Accessibility Extension by the Illinois Center for Information Technology and Web Accessibility (iCITA)
• developer extension for [1]
• Blank Your Monitor and Easy Reading Extension for Firefox
• plugin for Firebug
• contrast plugin for Firefox

Chrome extension

• Color Contrast Analyzer
• High contrast
• ChromeLens
• SEE
• Accessibility developer tools

Accessibility validation tools

• Chrome Accessibility Developer Tooks
• validation (for in Moodle, [2] and [3])
• Web accessibility evaluation tool
• Cynthia Says accessibility checker
• AXE
• WAVE

Screen readers

Since 2.7, Moodle officially supports the following screen reader/browser configurations (MDL-44002):

Browser	Screen reader	Minimum version	Recommended version
Microsoft Internet Explorer	Jaws	15	Latest
Mozilla Firefox	NVDA	2014.1	Latest

Other tools and resources:

• Fangs – the screen reader emulator for Firefox
• WebAIM Screen reader survey (Predominance of tools, browsers, OSs used by accessibility users)
• ChromeVox - Available in several languages for Linux, Windows and Mac OS, only on Chrome browser. (Android mobile users can use TalkBack)

See also this long list of accessibility tools.

See a live demonstration of a number of accessibility tools.

Resources

• Web Standards.org's Accessibility Task Force Manifesto
• Accessibility articles from A List Apart
• Mark Pilgrim's Won’t somebody please think of the gerbils?

Dive Into Accessibility by Mark Pilgrim

• Joe Clark's writings on accessibility

Building Accessible Websites by Joe Clark (online version)

• Wikipedia article on Web Accessibility
• Validity and Accessibility
• Videos showing as student accessing another Learning Management System via Screen Reader software

See also

• Accessibility statement - in current Moodle versions
• Semantic HTML
• Using Moodle New Accessibility Themes forum discussion
• See en:Usability FAQ for the related concept of usability.
• en:Moodle Accessibility Specification
• http://moodle.org/mod/forum/discuss.php?d=127807#p559951
• The Introduction to Moodle Programming provides some extensive information and discussion on accessibility.
• EASY: Interface Between The Virtual Environment Moodle Learning and People with Visual Impairments
• BBC blog post on how their Web 2.0 homepage was made accessible
• BBC Accessibility Help
• Accessibility Compliance in Moodle 1.8
• Compliance with Italian Legislation on Accessibility

Accessibility for Moodle Developers