Accessibility Testing Standard

Information conveyed by non-text content must be made accessible through the use of any sensory modality (visual, auditory or tactile) to match the needs of the user. For example, people who cannot see a picture can have the text alternative read aloud using synthesized speech. People who cannot hear an audio file can have the text alternative displayed so that they can read it. In the future, text alternatives will also allow information to be more easily translated into sign language or into a simpler form of the same language.

• Air Canada: Example of good alternative text description
• Niagara Falls: Example of missing alternative text descriptions.
  

Make information conveyed by prerecorded audio-only and prerecorded video-only content available to all users. An example of pre-recorded video with no audio information or user interaction is a silent movie. The purpose of the transcript is to provide an equivalent to what is presented visually. For prerecorded video content, authors have the option to provide an audio track. The purpose of the audio alternative is to be an equivalent to the video. This makes it possible for users with and without vision impairment to review content simultaneously. The approach can also make it easier for those with cognitive, language and learning disabilities to understand the content because it would provide parallel presentation.

• U.S. National Park Service: Example of Video description and american sign language

Captions provide the part of the content available via the audio track to enable people who are deaf or hard of hearing to watch synchronized media presentations. Captions not only include dialogue, but identify who is speaking and include non-speech information conveyed through sound, including meaningful sound effects. Captions are not needed when a synchronized media of the information is also presented via text on the Web page.

• W3C/WAI: Video demonstration of video captions

There are two approaches to provide people who are blind or visually impaired access to the visual information in a synchronized media presentation.
One approach is to provide audio description of the video content. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogue, audio description provides information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track.
The second approach involves providing all of the information in the synchronized media (both visual and auditory) in text form.

Captions provide the part of the content available via the audio track. Captions not only include dialogue, but also identify who is speaking and notate sound effects and other significant audio to enable people who are deaf or hard of hearing to watch real-time presentations.

Provide people who are blind or visually impaired access to the visual information in a synchronized media presentation. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogue, audio description provides information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track. If all of the information in the video track is already provided in the audio track, no audio description is necessary.

• YouTube: Lion King Audio Description
• ADP/ACB: Samples of Audio Description

Ensure that information and relationships that are implied by visual or auditory formatting are preserved when the presentation format changes. For example, the presentation format changes when the content is read by a screen reader or when a user style sheet is substituted for the style sheet provided by the author. Sighted users perceive structure and relationships through various visual cues. For example:

1. Headings are often in a larger, bold font separated from paragraphs by blank lines,
2. List items are preceded by a bullet and perhaps indented,
3. Paragraphs are separated by a blank line,
4. Items that share a common characteristic are organized into tabular rows and columns,
5. Form fields may be positioned as groups that share text labels,
6. A different background color may be used to indicate that several items are related to each other,
7. Words that have special status are indicated by changing the font family, or bolding, italicizing or underlining them; and so on.

Enable a user agent to provide an alternative presentation of content while preserving the reading order needed to understand the meaning. Content that does not meet this Success Criterion may confuse or disorient users when assistive technology reads the content in the wrong order, or when alternate style sheets or other formatting changes are applied.
The order of content in a sequence is not always meaningful. For example, the relative order of the main section of a Web page and a navigation section does not affect their meaning. They could occur in either order in the programmatically determined reading sequence. As another example, a magazine article contains several callout sidebars. The order of the article and the sidebars does not affect their meaning. In these cases there are a number of different reading orders for a Web page that can satisfy the Success Criterion.

Ensure that all users can access instructions for using the content, even when they cannot perceive shape or size or use information about spatial location or orientation. Some content relies on knowledge of the shape or position of objects that are not available from the structure of the content (for example, "round button" or "button to the right"). Some users with disabilities are not able to perceive shape or position due to the nature of the assistive technologies they use. This Success Criterion requires that additional information be provided to clarify instructions that are dependent on this kind of information.

Ensure that content displays in the orientation (portrait or landscape) preferred by the user. Some websites and applications automatically set and restrict the screen to a particular display orientation and expect that users will respond by rotating their device to match, but this can create problems. Some users have their devices mounted in a fixed orientation (e.g. on the arm of a power wheelchair). Therefore, websites and applications need to support both orientations by not restricting the orientation.
Many hand-held devices offer a mechanical switch or a system setting (or both) to allow the user to lock the device display to a specific orientation. Where a user decides to lock their entire device to an orientation, all applications are expected to pick up that setting and to display content accordingly.
The exception for things considered essential is aimed at situations where the content would only be understood in a particular orientation, or where the technology restricts the possible orientations. If content is aimed at a specific environment which is only available in one orientation (such as a television) then the content can restrict the orientation. Technologies such as virtual reality use screens within goggles that cannot change orientation relative to the user's eyes.

Ensure that the purpose of a form input collecting information about the user can be programmatically determined, so that user agents can extract and present this purpose to users using different modalities. The ability to programmatically declare the specific kind of data expected in a particular field makes filling out forms easier, especially for people with certain cognitive disabilities.
Appropriate visible labels and instruction can help users understand the purpose of form input fields. The input field label must clearly define the type of input and expected format. For example, assistive technologies may display familiar icons next to input fields to help users who have difficulties reading.

• W3C/WAI: example of a multi-part form with Accordion content

Ensure that all sighted users can access information that is conveyed by color differences, that is, by the use of color where each color has a meaning assigned to it. If the information is conveyed through color differences in an image (or other non-text format), the color may not be seen by users with color deficiencies. In this case, providing the information conveyed with color through another visual means ensures users who cannot see color can still perceive the information.
Color is an important asset in the design of Web content, enhancing its aesthetic appeal, its usability, and its accessibility. However, some users have difficulty perceiving color. People with partial sight often experience limited color vision, and many older users do not see color well. In addition, people using limited-color or monochrome displays and browsers will be unable to access information that is presented only in color.

• W3C/WAI: video Example of Colors with Good Contrast

Individuals who use screen reading software can find it hard to hear the speech output if there is other audio playing at the same time. This difficulty is exacerbated when the screen reader's speech output is software based (as most are today) and is controlled via the same volume control as the sound. Therefore, it is important that the user be able to turn off the background sound. Both the "pause or stop" and control of audio volume need to be independent of the overall system volume.
Playing audio automatically when landing on a page may affect a screen reader user's ability to find the mechanism to stop it because they navigate by listening and automatically started sounds might interfere with that navigation. Therefore, we discourage the practice of automatically starting sounds (especially if they last more than 3 seconds), and encourage that the sound be started by an action initiated by the user after they reach the page, rather than requiring that the sound be stopped by an action of the user after they land on the page.

Provide enough contrast between text and its background, so that it can be read by people with moderately low vision or impaired contrast perception, without the use of contrast-enhancing assistive technology.
Many different visual impairments can substantially impact contrast sensitivity, requiring more light-dark contrast, regardless of color (hue). For people who are not able to distinguish certain shades of color (often referred to as color blindness) hue and saturation have minimal or no effect on legibility as assessed by reading performance.
Text that is larger and has wider character strokes is easier to read at lower contrast. The contrast requirement for larger text is therefore lower. This allows authors to use a wider range of color choices for large text, which is helpful for design of pages, particularly titles.

Ensure that visually rendered text, including controls and labels using text, can be made larger so that it can be read more easily by people with milder visual impairments, without requiring the use of assistive technology (such as a screen magnifier).
Content satisfies the Success Criterion if it can be scaled up to 200% using at least one text scaling mechanism supported by user agents.
If the author is using a technology whose user agents do not provide support for specific text scaling mechanisms, the author is responsible for providing this type of functionality directly, or providing content that works with the type of functionality provided by the user agent. For instance, if the user agent doesn't provide full-page zoom functionality, but does let the the user change the text size, the author is responsible for ensuring that the content remains usable when the text is resized.

• W3C/WAI: Video example of Customizable Text

Images of text must allow people to be able to adjust the text presentation as needed. This includes people who require the text in a particular font size, foreground and background color, font family, line spacing or alignment.
If authors can use text to achieve the same visual effect, they should present the information as text rather than using an image.

Support people with low vision who need to enlarge text and read it in a single column. When the browser zoom is used to scale content to 400%, it should be presented in one column so that scrolling in more than one direction is not necessary.
For people with low vision, both enlarging and reflowing text are critical to reading. Enlarging text enables the perception of characters. Reflowing text enables users to track from the end of one line to the beginning of the next line.
Avoiding the need to scroll in the direction of reading in order to reveal lines that are cut off by the viewport is important, because such scrolling significantly increases the effort required to read. It is also important that content is not hidden off-screen. For example, zooming into a vertically scrolling page should not cause content to be hidden to one side.

• Level Access: YouTube video example of Screen Magnification & Reflow in Adobe Acrobat

Ensure that user interface controls and meaningful graphics are distinguishable by people with moderately low vision. Low contrast controls are more difficult to perceive, and may be completely missed by people with a visual impairment. Similarly, if a graphic is needed to understand the content or functionality of the webpage then it should be perceivable by people with low vision or other impairments without the need for contrast-enhancing assistive technology.

Ensure that when people override author specified text spacing to improve their reading experience, content is still readable and operable.
This criteria focuses on the adaptability of content to an increase in spacing between lines, words, letters, and paragraphs. Any combination of these may assist a user with effectively reading text. As well, ensuring that content correctly adapts when users override author settings for spacing also significantly increases the likelihood other style preferences can be set by the user. For example, a user may need to change to a wider font family than the author has set in order to effectively read text.

• W3C/WAI: video example of Clear Layout and Design

Additional content that appears and disappears in coordination with keyboard focus or pointer hover often leads to accessibility issues. Reasons for such issues include:

1. the user may not have intended to trigger the interaction
2. the user may not know new content has appeared
3. the new content may intefere with a user's ability to do a task

Examples of such interactions can include custom tooltips, sub-menus and other nonmodal popups which display on hover and focus. The intent of this success criterion is to ensure that authors who cause additional content to appear and disappear in this manner must design the interaction in such a way that users can:

1. perceive the additional content AND
2. dismiss it without disrupting their page experience.