Summary
Guidelines categorised must or must not are best practices that can easily be tested with specific criteria that is not subjective and is technologically possible to achieve with current assistive technology on mobile devices.
Guidelines categorised as should or should not are less testable but considered core to accessible mobile website and apps.
Principles:
- Use platform and web standards as intended
- Use standard interface controls where possible
- Support platform accessibility
Audio and video
Alternatives for audio and visual content must Alternative delivery, such as subtitles, sign language, audio description and transcripts, must be provided with embedded media when available.
Autoplay must not Audio must not play automatically unless the user is made aware this will happen or a pause/stop/mute button is provided.
Metadata should Relevant metadata should be provided for all media.
Volume control should Separate volume controls should be provided for background music, ambient sounds, narrative and editorially significant sound effects.
Audio conflict should not Narrative audio in games or interactive media should not talk over or conflict with native assistive technology.
Design
Colour contrast must The colour of text and background content must have sufficient contrast.
Colour and meaning must not Information or meaning must not be conveyed by colour only.
Styling and readability must Core content must still be accessible when styling is unsupported or removed.
Touch target size must Touch targets must be large enough to touch accurately.
Spacing should An inactive space should be provided around actionable elements.
Content resizing must Users must be able to control font sizing and user interface (UI) scaling.
Actionable elements must Links and other actionable elements must be clearly distinguishable.
Visible focus must When focused, all actionable and focusable elements must have a visible state change.
Consistency should A user’s experience should be consistent.
Choice must Interfaces must provide multiple ways to interact with content.
Adjustability should Interactive media, including games, should be adjustable for user ability and preference.
Flicker must not Content must not visibly or intentionally flicker or flash more than three times in any one-second period.
Editorial
Consistent labelling should Consistent labelling should be used across websites and native applications as well as within websites and applications.
Indicating language must The language of a page or app must be specified, and changes in language must be indicated.
Instructions should When needed, additional instructions should be provided to supplement visual and audio cues.
Focus
Focusable elements must All interactive elements must be focusable and inactive elements must not be focusable.
Keyboard trap must not There must not be a keyboard trap.
Content order must Content order must be logical.
Focus order must Actionable content must be navigable in a meaningful sequence.
Changing focus must not Focus or context must not automatically change during user input.
Appropriate triggers must Actions must be triggered when appropriate for the type of user interaction.
Alternative input methods must Alternative input methods must be supported.
Forms
Labelling form controls must All form controls must be labelled.
Input Format must A default input format must be indicated and supported.
Form Layout must Labels must be placed close to the relevant form control, and laid out appropriately.
Grouping form elements must Controls, labels, and other form elements must be properly grouped.
Images
Images of text should Images of text should be avoided.
Background images must Background images that convey information or meaning must have an additional accessible alternative.
Links
Descriptive links must Link and navigation text must uniquely describe the target or function of the link or item.
Links to alternative formats must Links to alternative formats must indicate that an alternative is opening.
Combining repeated links must Repeated links to the same resource must be combined within a single link.
Notifications
Inclusive notifications must Notifications must be both visible and audible.
Standard operating system notifications should Standard operating system notifications should be used where available and appropriate.
Error messages and correction must Clear error messages must be provided.
Feedback and assistance should Non-critical feedback or assistance should be provided when appropriate.
Scripts and dynamic content
Progressive functionality must Apps and websites must be built to work in a progressive manner that ensures a functional experience for all users.
Controlling media must Media that updates or animated content must have a pause, stop or hide control.
Page refreshes must not Automatic page refreshes must not be used without warning.
Timeouts must A timed response must be adjustable.
Input control should Interaction input control should be adaptable.
Structure
Unique page/screen titles must All pages or screens must be uniquely and clearly identifiable.
Headings must Content must provide a logical and hierarchical heading structure, as supported by the platform.
Containers and landmarks should Containers should be used to describe page/screen structure, as supported by the platform.
Grouped elements must Controls, objects and grouped interface elements must be represented as a single accessible component.
Text equivalents
Alternatives for non-text content must Alternatives must briefly describe the editorial intent or purpose of the image, object, or element.
Decorative content must Decorative images must be hidden from assistive technology.
Tooltips and supplementary information must not Tooltips must not repeat link text or other alternatives.
Roles, traits and properties must Elements must have accessibility properties set appropriately.
Visual formatting must not Visual formatting alone must not be used to convey meaning.
Recommendations
Offer a core accessible website
Use progressive enhancement
Link mobile and desktop sites
Minimise text fields