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WAI: Strategies, guidelines, resources to make the Web accessible to people with disabilities

Shared Web Experiences: Barriers Common to Mobile Device Users and People with Disabilities

This page describes many of the barriers that people with disabilities and people using mobile devices experience when interacting with web content, including web applications. It shows how these barriers are similarly addressed in W3C's Web Content Accessibility Guidelines (WCAG), Mobile Web Best Practices, and Mobile Web Application Best Practices.

Background

People with disabilities using computers have similar interaction limitations as people without disabilities who are using mobile devices. Both experience similar barriers when interacting with websites and web applications. There is also significant overlap between the design solutions for both. For more background, see:

A comprehensive comparison between MWBP and WCAG is provided in Relationship between Mobile Web Best Practices (MWBP) and Web Content Accessibility Guidelines (WCAG).

Introduction

The barriers on this page 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. (Mobile devices vary widely and not all the barriers are present on all models.)

This page includes links to some relevant solutions in:

The information below is also available in tabular format.

Contents

Perceivable

Information and user interface components must be presentable to users in ways they can perceive.

Experiences discussed below are also available in tabular format.

Information conveyed solely with color

User perceives color incorrectly or not at all, and so misses or misunderstands information or makes mistakes.

Disabilities Context: User who is blind or colorblind perceives color incorrectly or not at all.

Mobile Context: 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.

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Large pages or large images

User only sees small areas at a time, is unable to relate different areas of a page, and so becomes disoriented or has to scroll excessively. Additionally, user cannot access picture details because the picture is shrunk.

Disabilities Context: User with restricted field of vision or using screen magnifier gets only small part of page or image at a time.

Mobile Context: Mobile device has small screen (viewport).

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Multimedia with no captions

User misses auditory information.

Disabilities Context: User who is deaf or hard of hearing cannot hear.

Mobile Context: Mobile users often turn off sound in public places (trains, hotel lobbies); or often cannot hear in noisy places (streets, nightclubs).

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Audio-only prompts (beeps) for important information (warnings, errors)

User cannot operate or interact correctly with content, misses prompts, makes mistakes.

Disabilities Context: User who is deaf or hard of hearing cannot perceive content.

Mobile Context: Users often cannot hear in noisy (street, nightclub) or in public places (trains, hotel lobbies).

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Non-text objects (images, sound, video) with no text alternative

User cannot perceive important information or loses information due to lack of alternative.

Disabilities Context: User who is blind cannot perceive content that include non-text objects. Furthermore, information not available to user whose browser, assistive technology, other user agent doesn't support object.

Mobile Context: User can be billed for download volume so images might be turned off to save costs. Some mobile user agents have limited support for non-text objects so user loses information. Some user agents also shrunk images in size to fit the device's screen which can make images meaningless.

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Text entry

User has difficulty entering text so text is entered incorrectly or mistakes are made.

Disabilities Context: User with motor disability (for example, partial paralysis, hand tremor, lack of sensitivity, coordination) has difficulty entering information.

Mobile Context: Device has small keypad which has limited functionality compared to a full keyboard, or is held in an unsteady hand.

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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)

User cannot understand the content correctly when it's presented in a linear order.

Disabilities Context: User who is blind reads content in document tree order.

Mobile Context: Meaning of content can be changed because of reformatting or restructuring in adaptation process.

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Information conveyed only using CSS (visual formatting)

User is unable to access information encoded in visual formatting or in CSS.

Disabilities Context: User who is blind doesn't perceive visual formatting effects.

Mobile Context: Often no or limited CSS support or diverging CSS support by mobile browser.

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Operable

User interface components and navigation must be operable.

Experiences discussed below are also available in tabular format.

Mouse required for interaction and navigation

User is unable to navigate all content, or wastes time moving through numerous links.

Disabilities Context: Some users with a motor disability cannot use a mouse. Users who are blind also do not use the mouse.

Mobile Context: Device has no mouse, only alphanumeric keypad or joystick.

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Scripting required to operate content

User cannot operate the content so loses some information.

Disabilities Context: User's assistive technology or browser doesn't support scripting.

Mobile Context: Scripting turned off or not supported.

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Special plugin required

User can not perceive content or can not operate interface.

Disabilities Context: Plugin turned off, or not installed, or not compatible with assistive technology. Plugin not operable with preferred input device.

Mobile Context: Plugin turned off, or not installed, or not available; not compatible with input device (for example, requires mouse).

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Missing or inappropriate page title

User cannot easily scan to get an overview because of missing, inappropriate, or long page title.

Disabilities Context: User who is blind typically uses a screen reader feature to get a list of the currently open windows, by window title. Therefore, if the page title is long, inappropriate or missing, user cannot perceive the content.

Mobile Context: Page title truncated to fit narrow viewport of mobile device.

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Inconsistency between focus (tab) order and logical document content sequence

User is unable to navigate content in logical sequence, becomes disoriented.

Disabilities Context: User with motor disability uses keyboard for navigation not mouse. User who is blind also often use tab navigation to move from one element to another.

Mobile Context: Mobile devices may not have a pointing device so the user may have to navigate elements serially.

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User cannot determine to follow or not to follow a link because the link label is not descriptive enough.

Disabilities Context: User can not determine purpose of a link when read out of context. User who is blind often accesses a list of links on a page without the context around them.

Mobile Context: User can not determine purpose of link.

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Understandable

Information and the operation of user interface must be understandable.

Experiences discussed below are also available in tabular format.

Long words, long and complex sentences, jargon

User has difficulty understanding information.

Disabilities Context: Users with some types of cognitive disabilities have difficulty processing information. Users who are deaf and whose native language is sign, have difficulty processing complex written language.

Mobile Context: Text is displayed in small font, and user is often distracted by ambient conditions (background noise, conversations, moving objects in field of vision).

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Content spawning new windows without warning user

User becomes disoriented among windows; back button doesn't work. User closes window, not realizing it is last in stack, closing browser instance.

Disabilities Context: User with low vision, or restricted field of vision, or blindness, or cognitive disabilities doesn't realize active window is new.

Mobile Context: Single window interface. Multiple stacked windows on small screen hide each other.

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Blinking, moving, scrolling or auto-updating content

User has difficulty reading and comprehending content.

Disabilities Context: People with reading disabilities, cognitive limitations, and learning disabilities do not have sufficient time to read or comprehend information.

Mobile Context: Reduced size of mobile viewport or poor ambient lighting makes it difficult to see content. Auto-refreshed pages may also have cost implications if they are left open or put unnoticed into the background.

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Robust

Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies.

Experiences discussed below are also available in tabular format.

Invalid or unsupported markup

User cannot access the content because browser or adaptation system chokes on markup or rejects or garbles it.

Disabilities Context: User's assistive technology or browser cannot handle markup.

Mobile Context: Some older mobile browsers do not display content with invalid markup.

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Scripting required to generate content

User cannot access the content so loses some information because scripting is not supported by the user agent.

Disabilities Context: User's assistive technology or browser doesn't support scripting.

Mobile Context: Scripting turned off or not supported.

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