The Motive Web Design Glossary
Web accessibility is about enabling equal access to online content and services for all people, including those with visual and mobility impairment.
In practice, authoring an accessible website includes:
- structuring content using code that indicates information types and hierarchies (semantic markup); semantic markup enables a screen reader to emulate the process of scanning a webpage (using headings and link text) and read webpage content aloud
- marking-up content with ‘hooks’ that enable content to be effectively accessed with assistive technologies (such as screen readers)
- creating an interface that is device-neutral, for example supports keyboard alternatives to mouse-based interaction
Web content accessibility guidelines
The World Wide Web Consortium (W3C) has developed guidelines and tools
to aid the growth of the internet including Web
Content Accessibility Guidelines.
The guidelines (version 1.0) are grouped and prioritised according to their affect on accessibility.
Checkpoints that must be
met in order to met basic access requirements. Otherwise one or more
groups will be unable to access content.
For example; providing text equivalents for non-text elements (images), creating
an interface that is not reliant upon colour cues, and marking-up data tables
to distinguish column headers from data.
Checkpoints that should
be met in order to remove barriers to accessibility.
For example; using elements that distinguish information hierarchies (titles, headings, captions, paragraphs etc.), separation of form/presentation from content
(using stylesheets) and, providing
metadata for content pages.
Checkpoints that may
be addressed to improve accessibility otherwise one or more groups will
find it somewhat difficult to access content.
For example; expansion of acronyms and abbreviations, providing summaries
for data tables and grouping related links.
Accessibility, e-government and standards-compliance
…government-use requires equal-access to online information and services
A key driver for the implementation of accessibility guidelines has been government and government-agency use of the web.
Government-use requires equal-access be provided to online information and services—including access for those with visual or motor impairment.
In New Zealand equal-access has been legislated in the form of the New Zealand Government Web Guidelines and in the US through an amendment to the Workforce Rehabilitation Act: Section 508.
Code validation and accessibility
Valid code alone does not ensure that web content is accessible…
Web accessibility initiatives often include a validation process; checking the code of a webpage against a formal technical or applied standard, often using an automated service (validator).
One of the limitations of automated validation is a literal (non-contextual) interpretation of a standard. A validator can only be used to check the accuracy of markup and not whether or not the markup is appropriate.
For example, to increase the size of text an author could use a heading element:
<h1>This text will be larger</h1>
As the markup is ‘correct’ in terms of structure and syntax, it will both make the enclosed text larger and pass an automated validation test. However using semantic markup to create a visual effect is an inappropriate application of the standard.
Based on the use of the heading element (
<h1>), the text
‘This text will be larger’ is accorded a greater relative importance than the surrounding text. This ‘relative importance’ may then be reinterpreted, for example factored into search ranking for the webpage; or repurposed, for example used by a screen reader to quickly ‘scan’ content.
…validation [avoids] coding errors that may have an adverse affect on accessibility.
The key benefit of validation is in avoiding markup errors that may have an adverse affect on accessibility.
For example, failing to close an element may affect both the visual presentation and the semantic meaning of content. At its most extreme, poorly formed markup (or ‘tag soup’), can result in an unusable webpage.
Valid code alone does not ensure that web content is accessible—however content may be made more accessible through considered adherence to relevant technical and applied standards.
alt [tag] text, New Zealand Government Web Standards and Recommendations, Section 508, semantic markup, tags/elements, usability, validation
References and further reading
- 100,000 Reasons to design for accessibility (Bruce Lawson)
Is the need for web content to be accessible implicit in the purchase of web development services?
- Accessible data tables (Roger Hudson, Web Usability)
Methods for marking-up data tables to enable visually impaired uses to access to statistical information. The methods described include example code and the results of tests in a range of commonly-used screen readers.
- ARIA: Accessibile Rich Internet Applications (Mozilla Developer Center)
- Barrier-free web design, aka web accessibility 2.0 (Tommy Olssen, Roger Johansson, 456 Berea St.)
24 Oct 2006: Introducing the idea of universality: in essence designing with awareness of likely technological constraints such as connection speed, monitor size and user agent.
- Websafe colours (Motive)
Includes links to colour scheme accessibility evaluation tools.
- Delivering inclusive websites (The Central Office of Information, UK Government)
June 2008: Guidelines created by the UK Government setting a minimum standard of accessibility for public sector web content and web authoring tools.
- Designing for dyslexics (Mel Pedley, Access.org)
… Examining the specific learning difficulty known as dyslexia and how web design can impact the ability of those afflicted to access information on web pages.
- Dive into accessibility (Mark Pilgrim)
A scenario-based approach to implementing accessibility guidelines based on user personas. Provides a 30-day path to creating an accessible website.
- Essential components of web accessibility W3C
Accessibility depends on the interrelationship of; content, user agent, assistive technology, user knowledge, developer, authoring tools and evaluation tools.
- Getting started with accessibility assessments (AusWeb)
Techniques to identify common web-accessibility issues.
- The great accessibility camp-out (Gez Lemon vs Mike Cherim, Accessites.org)
1 Oct 2006: As people increasingly access the web from devices other than personal computers, there is pressure to expand the definition of ‘web accessibility’ to include designing for likely technological constraints and/or interoperability. Redefining the term has pros and cons…
- Google Accessible Search FAQ (Google)
A beta search service
designed to identify and prioritize search results that are more easily usable by blind and visually impaired users.
- Overdoing accessibility (Roger Johansson, 456 Berea St)
Misuse of HTML attributes intended to support accessibility (such as
tab index, and
alt), can do more harm than good.
- Policies [laws and legislation] relating to web accessibility (W3C)
Index of links to international government accessibility initiatives, grouped by country.
- Skills for access (University of Sheffield/University of Dundee)
Advice and information on multimedia, accessibility and teaching and learning. Includes case study examples of disabled people using multimedia resources in e-learning contexts.
- Skip link pros and cons (Mike Cherim and Gez Lemon, Accessites.org)
Screen reader users benefit more from well-structured content (i.e. use of HTML headings), than ‘skip link’ navigation. Users that are mobility-impaired need to see skip links to use them (and assuming keyboard/single-key interface, also need methods for by-passing other content and navigation blocks). If the links are visible, users with cognitive issues are confronted with additional, potentially confusing, navigation that they are unlikely to benefit from. Perhaps ‘skip link’ navigation should be filed under: ‘well-intentioned but practically useless’?
- Skip navigation (Jim Thatcher)
A range of methods for implementing ‘skip navigation’ links to assist those with visual or mobility impairment to by-pass repetitive navigation links to move to page content.
- The trouble with the
title attribute (Steve Faulkner, Vision Australia)
Although the title attribute was intended to improve accessibility, implementation of this feature varies from browser-to-browser. Includes example of how commonly-used browsers, including screen readers, interpret the title attribute.
- WAVE: Web accessiblity evalution tool (WebAim)
Enter a webpage address to view an onscreen accessibility evaluation.
- Web Content Accessibility Guidelines (WCAG)1.0 (W3C Recommendation)
- WCAG Samurai Errata (WCAG Samurai)
Corrections to WCAG v.1, drafted by an independent group of web developers as an alternative to adopting WCAG v.2.
- Web Content Accessibility Guidelines 2.0 (W3C Working Draft)
- Web design references: Accessibility (University of Minnesota Duluth)
A comprehensive directory of web-based accessibility references.
- Web standards and accessibility: [Why not universal access?] (Ricky Onsman)
15 Feb 2007: Views from a (former?) disabilities-services worker on the relationship between standards and accessibility, and expanding the definition of access.
Motive Web Design Glossary Trivia