Guidelines categorised as 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.
- 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.
- 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.
- 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.
- 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.
- User interactions : Must : Actions must be triggered when appropriate for the type of user interaction.
- Alternative input methods : Must : Alternative input methods must be supported.
- Labelling form controls : Must : All form controls must be labelled.
- Form inputs : 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.
- Managing focus : Must not : Focus or context must not automatically change during user input.
- 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.
- 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.
- 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.
- 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.
- Offer a core accessible website
- Use progressive enhancement
- Link mobile and desktop sites
- Minimise text fields