WAI: Strategies, guidelines, resources to make the Web accessible to people with disabilities
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The main content in this document is presented in a table format.
The same information is also available presented in topic sections.
Status: This document is a draft. The in-progress Editor's Draft is also available.
Please send comments to wai-eo-editors@w3.org (a publicly archived list).
People with disabilities (using desktop or laptop computers) and people without disabilities who are using mobile devices have similar interaction limitations and they experience similar barriers when interacting with Web sites. There is also significant overlap between the design solutions for both. For more information, see:
This page provides examples of barriers to interacting with Web content experienced by people with disabilities and people using mobile devices. Mobile devices vary widely and not all the problems are present on all models. These barriers are grouped under four principles: perceivable, operable, understandable and robust. These principles lay the foundation necessary for anyone to access and use Web content, as described in Understanding the Four Principles of Accessibility section of Introduction to Understanding WCAG 2.0.
This page also includes links to some relevant solutions in:
Information and user interface components must be presentable to users in ways they can perceive.
| Content | Disabilities context | Mobile devices context | Experience | WCAG 1.0 Checkpoint | WCAG 2.0 Success Criteria | MWBP 1.0 Best Practice |
|---|---|---|---|---|---|---|
Information conveyed using color (for example, “required material is shown in red”) with no redundancy. |
User who is blind or colorblind perceives color incorrectly or not at all. |
Many screens have limited color palette and color difference is not presented. Device is used in poor lighting (for example, outdoors), so colors are not clearly perceived. |
User perceives color incorrectly or not at all, and so misunderstands information, makes mistakes, or misses information. |
1.4.1
Use of Color, |
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Large page or large images. |
User with restricted field of vision or using screen magnifier get only small part of page or image at a time. |
Mobile device has small screen (viewport). |
User only sees small areas at a time ("keyhole view") or cannot access picture details because they are shrunk, unable to relate different areas of page, becomes disoriented or has to scroll excessively. |
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Multimedia with no captions |
User who is deaf or hard of hearing can't hear. |
Mobile users often in public places (trains, hotel lobbies) turn off sound; often in noisy places (streets, nightclubs) can't hear. |
User misses auditory information. |
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Audio-only prompts (beeps, buzzes) for important information (warnings, errors). |
User who is deaf or hard of hearing can't perceive content. |
Users often cannot hear in noisy (street, nightclub) or in public places (trains, hotel lobbies). |
Can't operate or interact correctly with content, misses prompts, makes mistakes. |
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Free-text entry (for example, alphabetical characters allowed in numeric fields) |
User with motor disability (partial paralysis, hand tremor, lack of sensitivity, coordination) has difficulty entering information. |
Device has small keypad, or is held in unsteady hand. |
User enters text incorrectly, makes mistakes. |
MINIMIZE
KEYSTROKES, |
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Embedded non-text objects (images, sound, video) with no text alternative. |
User who is blind or color blind can't perceive content. Information not available to user whose user agent doesn't support object or with slow connection making it unreasonable to wait for download. |
User with low bandwidth or who declines to run up connection charges. Already small images re-dimensioned even smaller in adaptation, become meaningless. |
Information loss due to lack of alternative. User can't perceive information. |
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Important information in non-text content (images, multimedia, CSS effects) |
User who is blind or colorblind can't perceive content. |
User billed for download volume, turns off images to save costs. Device has no CSS support. |
User misses important information. |
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Content formatted using tables or CSS, and reading order not correct when linearized (for example when CSS or tables not rendered). |
Non-visual (screen reader) user reads content in document tree order. |
Meaning of content altered by reformatting or restructuring in adaptation process. |
Content is garbled. |
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Information conveyed only using CSS (visual formatting). |
Blind user doesn't perceive visual formatting effects. |
Often no CSS support or diverging CSS support by mobile browser. |
Information lost or altered. |
User interface components and navigation must be operable.
| Content | Disabilities context | Mobile devices context | Experience | WCAG 1.0 Checkpoint | WCAG 2.0 Success Criteria | MWBP 1.0 Best Practice |
|---|---|---|---|---|---|---|
Interaction and navigation requires mouse. |
User with a motor disability may not be able to use a mouse. |
Device has no mouse, only alphanumeric keypad or rocker switch. |
User is unable to navigate all content, or wastes time moving through numerous links. |
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Scripting required to operate or generate content. |
User's assistive technology or browser doesn't support scripting. |
Scripting turned off or not supported. |
Information loss. Content inoperable. |
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Special plugin required. |
Plugin turned off, not installed, not compatible with assistive technology. Plugin not operable with preferred input device. |
Plugin turned off or not installed; not compatible with input device (for example, requires mouse). |
User can not perceive content or can not operate interface. |
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Long page title, with generic information first and differentiating information last |
Page titles are used to generate a list of links in site map, screen reader user, person with reading disability or reduced field of vision can't scan the page and reads repetitive information first. |
Page title truncated to fit narrow viewport of mobile device. |
User has difficulty reading list, misses important information at end of title. |
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Focus (tab) order does not match logical document content sequence |
User with (for example) motor disability uses keyboard for navigation not mouse. |
Pointing device not present or inadequate. |
User is unable to navigate content in logical sequence, become disoriented. |
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Link text not descriptive |
User can not determine purpose of link when read out of context |
User can not determine purpose of link |
Mobile user incurs delay and cost, due to network charges and device limitations. User with disability becomes confused or disorientated; arrives at inaccessible content. |
2.4.4
Link Purpose (In Context), |
Information and the operation of user interface must be understandable.
| Content | Disabilities context | Mobile devices context | Experience | WCAG 1.0 Checkpoint | WCAG 2.0 Success Criteria | MWBP 1.0 Best Practice |
|---|---|---|---|---|---|---|
Long words, long and complex sentences, jargon |
User with cognitive disability has difficulty processing information. |
Text is displayed in small font, and user is often distracted by ambient conditions (background noise, conversations, moving objects in field of vision). |
User has difficulty understanding information. |
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Content spawns new windows without warning user. |
User with low vision, restricted field of vision, or blindness doesn't realize active window is new. |
Single window interface. Multiple stacked windows on small screen hide each other. |
User becomes disoriented among windows; back button doesn't work. User closes window, not realizing it is last in stack, closing browser instance. |
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Content blinks, moves, scrolls or auto-updates |
People with reading disabilities, cognitive limitations, and learning disabilities do not have sufficient time to read or comprehend information. |
Reduced size of mobile viewport or poor ambient lighting make it difficult to see content. |
User has difficulty reading and comprehending content. |
Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.
| Content | Disabilities context | Mobile devices context | Experience | WCAG 1.0 Checkpoint | WCAG 2.0 Success Criteria | MWBP 1.0 Best Practice |
|---|---|---|---|---|---|---|
Invalid or unsupported markup. |
User's assistive technology or browser can't handle markup. |
Mobile device has embedded browser not supported by content provider. Content passes through adaptation processes. |
Browser or adaptation system chokes on markup; rejects or garbles it. |
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