Implementing UAAG 2.0

Intent of Success Criterion 1.1.1:

Users with some disabilities may find a specific content element causes them physical pain (e.g. an image with high contrast) or distress (e.g. an image that triggers post traumatic stress disorder), or that the element's size may make the page difficult to use (because of difficulty scrolling, or shifting gaze, or moving the pointer more than a certain distance). In these cases the user needs to be able to hide that element or replace it with alternative content or a placeholder. Other users may find specific elements are simply unusable (e.g. an image that is too low contrast for the user's vision). In these cases the user needs to be able to access author-provided alternative content (e.g. Alt text or Longdesc) or the very minimum a placeholder (e.g. filename).

Some users with disabilities need alternate languages or audio tracks (e.g. descriptive video). Users need the ability to choose tracks that best meet their accessibility needs (e.g. the caption track in their own language) when authors have provided many alternatives.

Note: If the user cannot directly select or choose the element in order to perform commands upon it (e.g. if the browser does not support clicking on HTML background images or moving focus to them with the keyboard), the user agent must provide an alternative user interface for this feature.

Examples for Success Criterion 1.1.1:

• Rodney has low vision and finds some images on a web page are painful to look at. He can hide foreground images by right-clicking on them or pressing the Tab key to move focus to them, and then choosing a command from the element's context menu. However, the browser does not let him right-click or navigate to the background image. Therefore it provides a user preference setting to hide all background images or to hide the background image on the current site.
• Carly has repetitive strain injuries and uses speech recognition to communicate with her computer. She's a paralegal and often has to search long documents for terms that are rendered as acronyms. It's often easier for her to speak full terms into the search box rather than acronyms because full terms are easier to say and better recognized, and this allows her to keep her vocabulary less cluttered by acronyms that may increase misrecognitions. She chooses a setting on her browser that automatically expands all acronyms and abbreviations before she does a search.
• Laura has impaired vision and uses the shapes of words to help her recognize them easily. It is more difficult for her to read strings of seemingly random upper case letters than strings of familiar words written with only their initial letters capitalized, so she changes her preference settings to have all abbreviations replaced by their expanded strings.
• Betty has an auditory processing problem. She is watching a movie that has several caption and audio tracks. She pulls up a menu to determine which tracks are available and switches between audio tracks until she find one she can understand. She also reinforces the audio by selecting a caption track.
• Marka is blind. She is listening to a video of a lecture. The professor is demonstrating a chemistry experiment and is not speaking during a key portion of the video. Since Marka cannot see what the professor is demonstrating, she brings up a menu of the available tracks and discovers that there is an audio description track available. Marka selects the description track, skips back, and listens to the description of the experiment.
• Gorges has profound hearing loss. He enjoys current run movies, and subscribes to a web service that streams major popular movies. Although he speaks English, he doesn't understand all the slang in the movie. He pauses the movie, selects a menu of caption tracks and finds a Spanish caption track. He watches the rest of the movie with Spanish captioning.

Related Resources for Success Criterion 1.1.1:

• Firefox extension "Text Equivalent Expand Abbreviations"

Intent of Success Criterion 1.1.2:

Users need to be able to easily discover when authors have provided alternative web content that may be of interest so they can decide whether to have it rendered (see Success Criterion 1.1.1). While the type of indicator is not prescribed, the success criterion requires that the indicator be placed along with the rendered content that has the alternative. This rules out indicators such as in the status bar, that don't clearly identify which content within a document has the alternative. Suitable indicators include outlines, adjacent icons, and adjacent links. As with any other feature of the user agent, the indicator itself must be accessible (e.g. keyboard accessible, alternative text, zoomable).

Examples for Success Criterion 1.1.2:

• Chris is color blind. He doesn't use a screen reader or other assistive technologies, but sometimes has difficulty interpreting diagrams where the author has used color alone to convey meaning (e.g. to label lines). Therefore, Chris likes to read long descriptions when the author has provided them. To let himself know when long descriptions are available, Chris sets a setting in his browser that places a "Description" link adjacent to any image with a long description. Chris clicks the link the open the long description in a new browser pane.
• Aosa is blind. When rendering a web page using synthesized speech, the user agent generates an audible tone to signify that the word being read is an acronym, and Aosa can press the * key to hear the expansion. When the phrase being read is the Alt text for an image, another tone indicates that Aosa can press + to hear the long description.
• [mobile] Brin is deaf. The video player she is using has a button displayed beneath the playing video that indicates that captions are available. She clicks the button to toggle the captions on so she can understand the video. On her mobile phone, Brin touches a video, which displays the controls including the "display caption" control.

Related Resources for Success Criterion 1.1.2:

• "HTML5 Image Description Extension (longdesc)" (http://www.w3.org/TR/html-longdesc/#longdesc)
• "User Agents and longdesc Discoverability" (http://www.d.umn.edu/~lcarlson/research/ld-ua.html)

Intent of Success Criterion 1.1.3:

Users may wish to hide images for a number of different reasons. Some users with cognitive disabilities may wish to hide images in order to avoid those that would be severely distracting. Some users with visual disabilities may wish to hide images in order to avoid those that are painful (such as those with high contrast). Other users may wish to replace images with alternative content because they are unlikely to be able to visually discern, understand, or otherwise benefit from the images. Some users with impaired motion or dexterity may wish to replace images with smaller alternative content to reduce the amount of scrolling they have to do, while some users with attention deficit disorder may wish to do the same thing in order to keep as much information visible on the screen as possible.

Examples for Success Criterion 1.1.3:

• Tyler has a learning disability and finds images very distracting. He sets a preference in his browser to always display alternative text instead of an image.
• [mobile] Ben has low vision and needs to use a very large font size to be able to read text. On his mobile device, enlarging the page makes any images so large that they use up too much screen space and require excessive scrolling. He sets a preference to render all images as text (if available) and to reflow the page so that the text flows smoothly with no space for the missing images.
• Lee has low vision where text is blurred. She finds that the transparency effect that shows detail "bleed through' under the window she is reading makes the text she is trying to read illegible. She sets a preference that hides all background images and transparency effects that the author may have written into a web page or application.
• James has a reading disability where he needs text to be clear from distractions that are not related to the text. He configures his user agent to not load background images. Then when he navigates to a web page, James gets only the text from the web page without any images interfering with what he is reading.
• Sasha requires high contrast to be able to discriminate the shape of letters. She always sets a preference in her browser to turn off background images, so that she can see the text clearly without the variations in the background.
• [mobile] Betty is a low vision user and has difficulty reading text on her mobile device when it is displayed over a background image. Using her user-defined style sheet, she can disable all background images from being rendered in her browser.

Related Resources for Success Criterion 1.1.3:

• 1.4.1 Configure Rendered Text for more information related to background colors.
• 1.1.4 Configure Alternative Defaults allows the user to hide foreground images by replacing them with alternative content, but 2.11.1 extends this to background images in languages such as HTML that do not support alternative content for background images.
• CSS 2.1: section 14.2.1 The Background In CSS, background images may be turned on/off with the background and background-image properties.
• CSS 2.1: section 9.9.1 Specifying the stack level: the 'z-index' property

Intent of Success Criterion 1.1.4:

Alternative content is wasted if the user agent doesn't render it for users who need it. Default alternative content is a global setting because it is an unreasonable burden for users to change the rendering options every time they visit a new page.

Examples for Success Criterion 1.1.4:

• Sally has low vision. In the browser's preferences dialog box, Sally specifies that she wants alt text displayed in place of images, and that the document should reflow to allow the entire alt text to be displayed rather than truncated.
• Ben has low vision. In the browser's preferences dialog box, he chooses to always display the alternative ("fallback") content for embedded objects, such as a transcript in place of a video.
• [mobile] Ben has low vision and keeps his mobile phone browser "zoomed" so he can read the text. Because images can become pixelated when enlarged, he prefers the alternative text. In the mobile settings dialog box, he chooses to always display the alternative ("fallback") content for images and to reflow the page without a placeholder for the image. This saves screen space and reduces the amount of scrolling he has to do.
• Brin is deaf. She toggles a menu item which turns on the display of all captions for video and audio content.

Related Resources for Success Criterion 1.1.4:

• Success criterion 1.1.4 adds additional required options to success criterion 1.1.3 Replace Non-Text Content.

Intent of Success Criterion 1.1.5:

Users who require or can benefit from alternative media tracks in video or audio may not find that the default or authored position and size of those tracks is usable. Enabling the user to move and scale any displayed alternate media tracks (e.g. captions) allows displayed content to be positioned and sized to meet the needs of the user.

Examples for Success Criterion 1.1.5:

• Justin has low vision and works in a noisy environment that makes it difficult to listen to instructional videos. When he enlarges the text of the captions to a viewable size, they block most of the video image. Justin selects an option that displays the caption track in a separate window, which he positions below the video image so the captions don't block the video image.
• Jaime is deaf and is taking courses from on online university. She prefers to use ASL if it is available for online media. A course she is taking offers captions and a signing avatar for the recorded lectures. The default size of the avatar window is small, making it difficult to follow the signing. The avatar also overlays a significant part of the lecture video. Jaime drags the avatar out of the video and enlarges it, so that they are side by side and equally sized.
• [mobile] Jaime is deaf and prefers to always display captions on her mobile phone. She has set her global settings on the phone to turn on closed captions. All videos displayed on the phone will automatically display captions.
• [mobile] Ben has low vision that becomes worse throughout the day as he becomes more tired. He keeps a floating control on his mobile phone that allows one touch access to his configuration so that he can change the font size. The floating control can be easily moved around the screen so it is not in the way of other controls, and it becomes translucent after it is idle for a few seconds.

Related Resources for Success Criterion 1.1.5:

• 1.4.1 Configure Rendered Text

Intent of Success Criterion 1.1.6:

Users may want to reposition the alternative in close proximity to the most important portion of the main media to reduce the visual scanning distance between them. For example, if the video frequently includes on-screen text near the top of the video then the captions will be easier to read if they are located above the video.

Examples for Success Criterion 1.1.6:

• Maximilian is hard of hearing and prefers to use captions. He adjusts the position of his captions depending on what he's watching. When watching a sporting event with a dashboard displaying statistics at the top, he positions the captions immediately above the top so the captions are close to the statistics. However, when he watches a movie, he positions the captions so that they overlap the video frame near the bottom. When he watches financial news with a stock ticker along the bottom, he moves the captions to be immediately below the ticker.
• [mobile] Raymond has one functioning hand. He positions captions so that they're not covered by the hand he's using to hold his tablet.
• [mobile] Tom is deaf. When Tom watches narrow-aspect video on a wide-aspect screen or in landscape mode on his mobile device, he moves the window displaying sign language interpretation to the side, allowing the primary video to take up the entire height of the screen without the interpretation getting in the way.

Related Resources for Success Criterion 1.1.6:

• None

Intent of Success Criterion 1.2.1:

When alternative content is missing, it can be helpful for users to access metadata such as the filename, which can be substituted as repair text. However, these are not as helpful as alternative content that's properly authored for the original document. In these cases assistive technology can provide users with information that may be more helpful than any one piece of repair text the user agent could provide. Therefore it's important that assistive technology have access to as much information as possible about the non-text content that needs repair, and also to be able to inform the user that no author-provided text alternative is available. User agents should provide assistive technology with available metadata for the non-text content that needs repair, but not substitute repair text in ways assistive technology will mistake for author-provided text alternatives.

Examples for Success Criterion 1.2.1:

• Ray is blind and counts on alternative text for images. When his screen reader is reading a web page and encounters an image, it asks the user agent for alternative text. If the user agent reports that no alternative text is available, the screen reader accesses the DOM to retrieve the title attribute associated with the image, its original file name, and path to the downloaded image file. It extracts embedded metadata from the image file, such as its original title and caption fields. It can then tell Ray that there is an image with no alternative text, provide him with the value it considers most likely or that Ray has selected through his preferences, then provide a command that lets him hear the other values so he can make his own judgement about the nature and purpose of the image.

Related Resources for Success Criterion 1.2.1:

• None

Intent of Success Criterion 1.2.2:

When an author neglects to provide labels and/or headers as necessary for accessibility, the user agent can sometimes use heuristics to determine potential labels and/or headers from presentation attributes. Once potential headings and/or labels have been identified, the user agent can proceed (e.g. with communication via platform accessibility services) as if the relationship was defined in the markup. The user can specify whether heuristics should be applied because some users want to experience the content as the author provided it (e.g. to perform evaluations or when heuristics fail).

Examples for Success Criterion 1.2.2:

• Frank uses speech input. When content markup includes a checkbox without a specified label, the user agent detects that a static text component is positioned immediately to the right of the checkbox and no other static text components are nearby. The nearby text is treated as the label. This enables Frank to toggle the checkbox by speaking its name.
• Maria uses a screen reader. When a table lacks marked up header rows, the user agent gives her the option to have the first row treated as the table header row.
• Li uses a scanning keyboard and makes use of the user agent's outline view to more efficiently navigate web pages. The content markup includes instances of static text that differ from surrounding text because they are sentence fragments and styled with a larger font and bold weight. The instances are treated as headings as therefore appear in the outline view, enabling Li to more efficiently navigate to them.

Related Resources for Success Criterion 1.2.2:

• Understanding WCAG 2.0: Heading and Labels

Intent of Success Criterion 1.3.1:

Users need to be able to easily discover web content they can interact with. One effective way to do this is to highlight enabled elements and links (including recently visited links). Highlighted selection and content focus lets people who use keyboard, gesture and speech input know where they are working. On some pages controls may be difficult to discern amid a large amount of other content, or may be styled so the controls are difficult to distinguish from other content. This can be particularly difficult for people with visual impairments, who may not be able to distinguish subtle visual differences. People with some cognitive impairments may have difficulty distinguishing between items with similar or non-standard appearance. Visually distinguishing these items reduces the amount of time or number of commands these groups require to examine a page.

• Note 1: In addition to these required categories, it is recommended that user agents also allow the user to highlight the active viewport, even when it is a frame or similar within the active window. This makes it much easier for the user to visually locate the active focus.
• Note 2: Platform conventions will dictate whether or not keyboard focus in an inactive viewport is visually indicated by an inactive cursor.
• Note 3: the definition of visited and unvisited links is up to the user agent. Visited links may be links visited during the current session or in the browser's history.

Examples for Success Criterion 1.3.1:

• Jerry has low vision. He goes to a website that uses Cascading Style Sheets (CSS) to override visited link color. He wants to know what links have yet to be explored. The user agent provides a dialog box for setting overrides to author-selected link colors. Jerry uses the dialog box to override these so visited links are indicated.
• Jerry goes to a website with styles that remove the content focus outline. The user agent provides a dialog box for setting overrides to the author's focus outline declaration. Jerry uses the dialog box to display the content focus outline so he can tell where the focus is on the page.
• Binh gets easily frustrated when he cannot locate the buttons and links on a page. This happens when buttons and links don't have the standard appearance he's used to. The user agent provides a dialog box for setting overrides to author-selected link colors. Binh turns on the option to have all links appear in bright purple, and buttons drawn with a bright purple border so he can easily scan the page and find the items he's looking for.
• [mobile] George has limited hand use and uses custom gestures on his mobile phone. He wants a visible focus indicator to know what element on the page has focus so when gestures are used on the mobile phone, he will know what element will be activated.
• Aosa is blind. When rendering a web page using synthesized speech, the user agent generates an audible tone to signify that the word being read is an acronym, and Aosa can press the * key to hear the expansion. When the phrase being read is the Alt text for an image, another tone indicates that Aosa can press + to hear the long description.
• [mobile] Brin is deaf. The video player she is using has a button displayed beneath the playing video that indicates that captions are available. She clicks the button to toggle the captions on so she can understand the video. On her mobile phone, Brin touches a video, which displays the controls including the "display caption" control.

Related Resources for Success Criterion 1.3.1:

• 1.3.2 Highlighting Options describes user options to configuring how these categories are highlighted
• 2.1.2 Keyboard Focus requires every window have an active or inactive keyboard focus at all times
• 1.8.1 Highlight Viewport provides guidance for highlighting viewports
• 1.8.2 Move Viewport to Selection and Focus provides guidance for highlighting an active window

Intent of Success Criterion 1.3.2:

Low vision users and users with some cognitive disabilities need control over visual properties to meet their individual needs. These include foreground colors, background colors, and visual borders (with the same configurable range as the operating environment's conventional selection utilities)

Examples for Success Criterion 1.3.2:

• Alex has low vision. He sometimes has difficulty distinguishing fields on web forms. The user agent provides a dialog box allowing the user to override any author settings. He chooses to have all form fields displayed with a yellow background and outlined with a thick black border.
• Marcy has a cognitive disorder that makes it difficult to stay focused on the task she wants to accomplish. The user agent provides a dialog box allowing the user to override any author settings. She chooses to have all form fields displayed with a yellow background and outlined with a thick black border.

Related Resources for Success Criterion 1.3.2:

• CSS 2 specification – box border styles

Intent of Success Criterion 1.4.1:

Users with some types of disabilities have difficulty reading text as the author has formatted it. For example, some users with low vision, dyslexia, and related conditions and situations cannot read author-formatted text. However, they can read text that has a format customized to their individual needs (e.g. larger letters, different font, more spacing). Users with some cognitive disabilities and those who need to reduce the number of commands they enter to scroll through a document, may need to fit more information on the screen (e.g. smaller letters or spacing). Users need to access a wide range of font sizes, styles, colors, and other attributes in order to find the combination that works best for their needs. In providing preferences, it is important to avoid making assumptions. For example, some users may increase font size to make text more legible, while other users may reduce the font size to decrease the need to scroll the content.

The relative size of text provides visual cues that help in understanding and navigating web content. Some content may be authored in a way that makes it difficult or impossible to understand when font distinctions are hidden, such as headlines that are in not in a larger font than body text. It's important that users who need to enlarge or reduce text size be able to preserve these visual cues.

Examples for Success Criterion 1.4.1:

• Lee has low vision from albinism and when the background is white, it is hard for her to read and hurts her eyes. She changes the colors in her operating system to white text on a black background. However, many web pages specify their own colors, so she adjusts the user preferences in her browser to always use the system colors (or another set of colors of her choosing), regardless of how the pages are authored.
• Betty Sue has low vision from nystagmus and has difficulty seeing small fonts. The browser on her laptop provides five font sizes. However, the largest isn't big enough. The browser settings provide an option to override the five font sizes with customized font range, so that Betty Sue can select the specific font size she needs.
• Mike has a reading disability. A website uses a fancy script font for the headings that he cannot understand. He uses his browser's font settings to select plain fonts that he can read.
• [mobile] Ben has low vision. In the mobile settings dialog box, he chooses a large text for font size. All applications on the mobile phone display text in large font.
• Sebeeya has low vision. She finds text easiest to read at 16 pt Palatino and chooses to have her browser display body text in the 16 pt Palatino font. She needs the headlines to scale proportionally (e.g. 24 pt) in order to preserve headline prominence.

Related Resources for Success Criterion 1.4.1:

• Guideline 1.7 Enable Configuration of User Stylesheets
• Success Criteria 1.8.5 Allow Zoom
• Success Criteria 1.8.7 Reflow Text
• Success Criteria 1.8.9 Allow Viewport Resize

Intent of Success Criterion 1.4.2:

Some users with low vision, dyslexia, and related conditions and situations cannot read normally-formatted text. However, they can read text that has a format customized to their individual needs (e.g. larger letters, different font, more spacing). Users need to access a wide range of font sizes, styles, colors, and other attributes in order to find the combination that works best for their needs. In providing preferences, it is important to avoid making assumptions. For example, some users may increase font size to make text more legible, while other users may reduce the font size to decrease the need to scroll the content.

Users who need large amount of screen magnification need to control the appearance of types of elements. For instance, a magnification of 300% can make headlines too large for display. Users need to be able to set the characteristics of element types (e.g. heading 1, heading 2, table heading) to make the web content readable. Magnification users who find that text size distinction greatly increases scrolling and fatigue also need to be able to display important elements such as headings (including table headings) and input fields independently from global settings.

Examples for Success Criterion 1.4.2:

• Tomas has low vision and uses a screen magnifier. He chooses to have his browser display all text the same size, and sets that size as large as he can without making the letters too tall for his screen. Tomas chooses not to have headings be proportionately larger than normal text because that would make them taller than his screen and so unreadable. He uses a user stylesheet to make the different levels of headings a different color. He makes the table headings bold so they stand out from the table text without significantly increasing the size.
• Adele is 84 and has macular degeneration and is experiencing fine motor problems. She loves using her mobile tablet to read her email and follow her grandchildren on social media. She has difficulty selecting text areas to enter forms. Her granddaughter helps her create a font size setting for input fields so that the text is larger and increases the area where she can tap, making it easier to enter text.

Related Resources for Success Criterion 1.4.2:

• Guideline 1.3 Provide highlighting for selection, keyboard focus, enabled elements, visited links
• Guideline 1.7 Enable Configuration of User Stylesheets
• Success Criteria 1.8.5 Allow Zoom
• Success Criteria 1.8.7 Reflow Text
• Success Criteria 1.8.9 Allow Viewport Resize

Intent of Success Criterion 1.4.3:

Some users with low vision, dyslexia, and related conditions and situations cannot read normally-formatted text. However, they can read text that has a format customized to their individual needs (e.g. larger letters, different font, more spacing). In providing preferences, it is important to avoid making assumptions. For example, some users may increase font size to make text more legible, while other users may increase font spacing to improve readability.

Calculating font height and base character width can be complicated. For accessibility purposes, the formula is not important as long as the result gives users multiple choices of font height and character kerning. For UAAG 2.0 purposes, it does not matter what unit of measure is used, as long the multiples of that unit are provided.

Many users with low vision have difficulty reading italic and underline and must be able to globally remove these styles. This can be accomplished with user stylesheets, but if the browser doesn't support user stylesheets, the browser needs to provide this ability through settings.

Many users with autism or reading disabilities have difficulty reading justified text, because uneven spacing can create distracting "rivers of white". These users need to be able to change fully justified text to left or right justified depending on the text language.

Examples for Success Criterion 1.4.3:

• Suzanne's vision has deteriorated due to aging and she has had cataract surgery. When she reads blocks of text that have normal spacing, the text becomes a gray mass and Suzanne cannot skim or track from the end of one line to the next. In one browser she uses a toolbar that doubles the line spacing. For another browser, a friend coded a bookmarklet that Suzanne uses to double the line spacing.
• Abdullah has dyslexia and low vision, and has trouble telling letters and words apart. When he increases the character spacing and word spacing he can better distinguish each letter and understand the words. When text is underlined, such as links, it makes it hard for him to read, so he turns off underlining.
• Jamee has dyslexia that makes it hard for her to keep her focus on words. When text is fully justified, there are sometimes lots of space between words and in long paragraphs of text, these create "rivers of white". She sees the spaces and has trouble focusing on the words. When Jamee changes from full justification to left justification, there is normal space between words and she can read much more easily with less fatigue.

Related Resources for Success Criterion 1.4.3:

• Guideline 1.7 Enable Configuration of User Stylesheets
• Success Criteria 1.8.7 Reflow Text
• CSS 2 Letter and word spacing
• CSS 2 10.8.1 Leading and half-leading

Intent of Success Criterion 1.4.4:

The ability to print content is important for users who have difficulty reading or interacting with Web content directly in the user agent due to software, hardware, or ergonomic issues. Printing to virtual printer devices can also be a necessary step in converting the content to another electronic format that the user finds more accessible. It is also important that the user be able to print content with modifications they have applied, such as scaling or highlighting, or else they may find the printed version unusable. At the same time, they need to be able to have content reflowed to fit the width of the page, or else content may be cut off.

User agents are strongly encouraged to let the user print a portion of the document, such as a selection or specified range of pages, because otherwise printing won't be a practical option for long documents.

Examples for Success Criterion 1.4.4:

• Jamee has dyslexia that makes it hard for her to keep her focus on words. If she tries to read much online, she loses her place. Therefore, she often prints text then uses a blank piece of paper to cover up the line below where she is reading.
• Ansgard has multiple sclerosis that causes low vision, fatigue, and muscle spasticity. He cannot sit and read from his computer for very long at a time, so Ansgard prints long articles and reads them in a more comfortable position. He wants to configure the text to be readable and to use as little paper as possible, so he sets large text overall, making headings the same size, then he makes headings bold and underlined to stand out. Ansgard sets overall margins narrow to get more text on a printed page.
• Ralph finds it moderately difficult to use the computer as he ages, so while he can operate the Web browser, he finds long documents much easier to read when he prints them out so that he can hold them in a more comfortable position. When a web page has small text, he enlarges it on the screen using his web browser's Zoom command, which also makes the printed text large enough for him to read.

Related Resources for Success Criterion 1.4.4:

• Guideline 1.7 Enable Configuration of User Stylesheets
• Success Criteria 1.8.7 Reflow Text

Intent of Success Criterion 2.1.1:

A user has many ways to input information into a computer or device, including mouse, keyboard, gesture, and speech. The keyboard paradigm is the most universal interface for text input – even devices that do not have a keyboard (like mobile phones) support a software interface for them. A user should be able to navigate, read and use all of the web page or application without needing to use a mouse. Some users do not use a mouse. Others can only use a pointing device that uses the keyboard API. It's important that these users be able to interact with enabled components, select content, navigate viewports, configure the user agent, access documentation, install the user agent, and operate user interface controls, all entirely through keyboard input. User agents generally support at least three types of keyboard operation:

1. Direct (e.g. keyboard shortcuts such a "F1" to open the help menu; see checkpoint 11.4 for single-key access requirements)
2. Sequential (e.g. navigation through cascading menus)
3. Spatial (e.g. when the keyboard is used to move the pointing device in two-dimensional visual space to manipulate a bitmap image)

User agents should support direct or sequential keyboard operation for all functionalities. The user agent should offer a combination of keyboard-operable user interface controls (e.g. keyboard operable print menus and settings) and direct keyboard shortcuts (e.g. to print the current page).

Examples for Success Criterion 2.1.1:

• Amal has a medical condition that prevents him from using the mouse. Jeremy finds it difficult or impossible to use a mouse or keyboard and therefore uses speech to control the keyboard. Tanya is blind and uses a screenreader and must be able to accomplish all tasks with the keyboard. Jamie uses a switch device to control the computer. Each of these users must be able to do the following through keyboard alone, speech input alone, or switch device alone:
  • Select content and operate on it. For example, if it is possible to select rendered text with the mouse and make it the content of a new link by pushing a button, these users also need to be able to do so through the keyboard and other supported devices. Other examples include cut, copy, and paste.
  • Set the focus on viewports and on enabled elements.
  • Install, configure, uninstall, and update the user agent software.
  • Amal, Jeremy and Jamie use the graphical user interface menus even though they cannot use the mouse.
  • Fill out forms.
  • Access documentation.
• Amal is reading a web page where the author used the CSS overflow property to constrain the size of a block of content. Amal's browser provides scroll bars to display text that overflows the viewport. He uses the keyboard to enter the element and operate the scrollbars to read all the content, he then uses the keyboard to return focus to the main web page. (see 2.1.3 No Keyboard Trap)
• Tanya needs to use a volume control widget to change the volume on a video she is watching. She use the keyboard to navigate to the widget, uses the arrow keys to increase the volume, then uses the keyboard to navigate to the comments below the video player.
• Cade has low vision. He can't identify an icon and so he needs to read its alternative text. Mouse users could hover the mouse over the icon and have its alternative text displayed as a pop-up or tooltip, but Cade cannot use a mouse. He uses the keyboard to move focus to the icon. The browser automatically displays the "hover" tooltip, or allows him to press a key to have it displayed.
• Jeremy is a speech-input user who cannot use his hands to control his computer. It is much easier for him to speak keyboard shortcuts then click on an icon in a new program. He needs to be able to see tooltips to discover keyboard shortcuts without having to use the mouse.
• [mobile] Karen has muscular dystrophy and cannot easily use the onscreen keyboard to navigate web pages on her mobile phone. Instead, she uses simple gestures to move between elements on the page. As focus moves from one element to another, there is a visble focus indicator.

Related Resources for Success Criterion 2.1.1:

• Modality Independent Controls
• 2.1.3 No Keyboard Trap

Intent of Success Criterion 2.1.2:

Both the user and some types of assistive technology need to know what will be affected by any keyboard input, so it's important that they be able to tell which window, viewport, and controls have the keyboard focus at any time. This applies whether window and viewport are active (active keyboard focus) or inactive (inactive keyboard focus). Even when a window is inactive, it can be affected by simulated keyboard input sent by assistive technology tools. Active keyboard focus is indicated to the user by focus cursors and text cursors, as required by Guidelines 1.3, and made available to assistive technology, as required by Success Criterion 4.1.6.

Examples for Success Criterion 2.1.2:

• Amal has a medical condition that prevents him from using the mouse. He launches a web browser and navigates to a web page. Initially the keyboard focus is on the entire document, which is exposed to assistive technology, but there is no visible cursor. When Amal presses the tab key, the focus moves to the first link on the web page, and a cursor in the form of a dotted rectangle appears around that link.
• Amal launches a web browser and navigates to a web page that has an enabled edit field. The browser places the keyboard focus on the edit field so Amal can immediately start entering text, and its location is shown using a text cursor (usually a vertical line or i-beam). As he types, the text cursor moves to show where the next character will appear. If Amal activates another window, the browser may hide the cursor in the now inactive window, but its location is still available to assistive technology.
• Raymond has low vision. As the keyboard focus moves from one control to another, or one window to another, his screen enlarger utility detects the focus change and pans its viewport to keep the focus location visible.
• [mobile] Jeremy is a speech-input user who cannot use his hands to control his tablet. He opens a webpage using a speech command. The webpage has a search field, and normally comes up with the keyboard focus in the search field. Jeremy sees the indicator in the search field and knows he does not have to navigate to the search field before saying a search term.
• [mobile] Erin has dyslexia which often causes her to confuse directions. She uses gestures to navigate her mobile phone. As focus moves from one element to another, there is a visble focus indicator, which allows her to find the focus easily.

Related Resources for Success Criterion 2.1.2:

• Guideline 1.3 Provide highlighting for selection, keyboard focus, enabled elements, visited links
• 4.1.2 Expose Basic Properties ensures that the focus location is available to assistive technology.

Intent of Success Criterion 2.1.3:

If users can put focus on an element, they can remove focus and move on to the next element. This is often not possible with embedded objects. The user agent needs to provide a way to always return to the previous or next element in the content, or a known location such as the address bar. The user agent also needs to take control back from the embedded object, no matter what it is.

Examples for Success Criterion 2.1.3:

• Ari has repetitive strain injuries that are exacerbated when he uses the mouse. He is using a video hosting site where each page hosts a nested media player. He presses Tab until the focus in on the media player, then presses Enter to activate and put the keyboard focus on it. When he's finished watching the video, he presses Tab to navigate to the comments below the video, but cannot get the focus to leave the video player. He presses Alt+Left to return to the previous page, but that also fails because the video player is consuming those keystrokes. Luckily, Ari knows that Shift+Esc will return focus from a nested user agent, with or without its cooperation. Thus, even a badly behaved nested user agent cannot prevent Ari from getting on with his work.
• Ari moves the focus to a toolbar extension that does not relinquish control back to the user agent. He presses Alt-D to move the focus to the address bar.
• Mary is a blind user who does not use the mouse. She moves the focus to an embedded scripted application that was poorly programmed. She presses a documented key combination –  Alt+N – to override the scripting and move the focus to the next element in the content.
• Katan cannot use the mouse and has trouble with short-term memory. He is using a virtual machine. The escape sequence is Shift+Ctrl+Escape. Every time Katan opens the program, it briefly shows the escape sequence near the top right corner of the screen.  The virtual machine also has an Exit option in its menu system. The Escape keystrokes are also indicated on the menu.

Related Resources for Success Criterion 2.1.3:

• None

Intent of Success Criterion 2.1.4:

People do not expect side effects when moving the keyboard focus regardless of whether the side effect is caused by the user agent or author content. If users fail to notice side effects, they could end up doing something disastrous. This is especially likely for users of assistive technology who cannot see changes happening elsewhere on the screen. Users may also find it confusing or disorienting if the effect causes unexpected focus movement or changes in context. If the user agent does implement side effects to keyboard navigation, it is recommended that it provide a user preference setting to disable them. However, in some cases it may be more appropriate to provide a separate navigation mechanism that avoids side effects, such as allowing the user to hold down the Ctrl key while navigating to avoid changing selection or choice. Note: It may not be possible for the user agent to detect or prevent side effects implemented by scripts in the content, but the user agent is required to prevent side effects that are under its control.

Examples for Success Criterion 2.1.4:

• Murray uses a screen magnifier that allows him to see the element with the focus and a small area around it. He explores a dialog box by repeatedly pressing the Tab key to move to, and read each control in succession. He uses the arrow keys to navigate through a dropdown menu. When he moves the focus to the first option he goes to that page. He wants to navigate to the third selection, but can't get there. Fortunately, the platform also has a convention that holding down the Ctrl key while navigating that moves the focus without changing selection or option choice. Murray uses this while exploring. His web browser implements its own form controls and navigation mechanisms rather than using the platform's infrastructure, but also implements this Ctrl-key mechanism for users like Murray.
• [mobile] Ari uses the screen reader on his smartphone to navigate a webpage. He selects an item and is able to activate the element using gestures. This requires sufficient screen real estate to perform gestures without changing focus.
  

Related Resources for Success Criterion 2.1.4:

• WCAG 2.0: 3.2.2 - On Input
• WCAG 2.0: 3.2.5 Change on Request
• WCAG Techniques: SCR19: Using an onchange event on a select element without causing a change of context
• WAI-ARIA: aria-selected (state)
• 1.8.12 Allow Top-Level Viewport Focus Control

Intent of Success Criterion 2.1.5:

Keyboard users rely on the user agent to provide keyboard support that is full-featured and consistent among applications. Following platform conventions for keyboard access helps ensure that the functions that people rely on are not accidentally omitted. In addition, making these inputs consistent within and across programs greatly reduces learning curve, cognitive load, and errors. User agents are encouraged to add keyboard commands when the commands provide additional features or benefit for users. User agents should avoid omitting the standard commands, or assigning them to different keys.

Examples for Success Criterion 2.1.5:

• Jack is blind and uses a screenreader. He edits blog posts in his browser's text area control, and can use the same keys for navigation, editing, and formatting that he's used to using in other applications on the platform (e.g. arrow keys, commands to move to the beginning and end of the line, cut, copy, paste, ctrl-b for bolding).
• Jack's user agent uses a custom tree control showing a hierarchical outline view of the document headings. He can navigate within that control using the same keys as work in the native tree controls used in other applications (e.g. up, down, left and right arrow keys, and navigating directly to entries by typing the beginning of their text).
• Jack puts his browser into a caret browsing mode so he can move the text cursor through the text on the page. The browser supports the same keys for navigation and editing as are used in other applications.

Related Resources for Success Criterion 2.1.5:

• None

Intent of Success Criterion 2.1.6:

Efficient keyboard navigation is especially important for people who cannot easily use a mouse, are quickly fatigued, or find it difficult to memorize the menu structure for sequential navigation. This is important in all types of user agent environments.

• In a browser: A browser provides keyboard shortcuts for its menu functions as well as access keys in the design of its menus and dialog boxes. The choice of shortcut keys follows platform conventions where applicable (e.g. for open document, save document, cut, copy, paste).
• In a mobile environment: A social networking application on a mobile device has only a very few keyboard shortcuts available on its targeted devices. These few keyboard shortcuts are used for the most commonly accessed functions of the application (e.g. home, list of friends).
• In a media player: An embedded media player provides shortcut keys for commonly used functions (e.g. pause and play).

Examples for Success Criterion 2.1.6:

• Jack is blind and uses a screenreader. He opens his browser to write his email. He uses a shortcut to start a new message. He uses the same Ctrl-N command he uses in his desktop email application.
• Jean has a medical condition that makes it difficult to visualize complex visual structures like dropdown menus. She is writing a new blog entry and discovers that her blogging application has updated and all the menus have changed. She cannot find the menu option to format the text, but is pleased to find that Ctrl-B still works to bold the text she wants.
• [mobile] George is blind and uses the gestures on his mobile device to move focus to the top of the page, return to the previous web page and activate links.

Related Resources for Success Criterion 2.1.6:

• 5.1.3 Implement Accessibility Features of platform

Intent of Success Criterion 2.2.1:

Sequential keyboard navigation is a fundamental, universal method of keyboard access. While it can be slower and require more input than other methods (such as direct, structural, or search-based navigation) it is a simpler mechanism that requires very little cognitive load or memorization, and is consistent across contexts. Users need keyboard access to all viewports and all enabled elements so that they can manipulate them, view them with screen magnifiers, or have them described by screen readers. The ability to move both forward and backward through the navigation order greatly reduces the number of keystrokes and allows the user to more easily recover from mistakes in overshooting a destination.

Examples for Success Criterion 2.2.1:

• Sooj cannot use a pointing device, so she moves the keyboard focus to the next enabled element by pressing the Tab key, and to the previous enabled element by pressing Shift+Tab. Within list boxes and radio button groups she uses the up and down arrow keys to move to the next and previous items.
• [mobile] George is blind and uses a screenreader on his computer and the speech output and gesture features of his mobile phone. When completing a web form on his phone, he uses the swipe gesture to advance through the form. If George goes past the next form field, or wishes to return to a previous form field, he can use a gesture to go backward.

Related Resources for Success Criterion 2.2.1:

• 2.3.1 Direct Navigation to Important Elements
• The following is a non-exhaustive list of keyboard shortcut conventions for various platforms (from ATAG 2.0):
  • Desktop OS
    • GNOME Desktop on Linux: GNOME Human Interface Guidelines 2.2 - Keyboard Interaction
    • Mac OS: Mac OS X keyboard shortcuts
    • Microsoft Windows: Keyboard Shortcuts for Windows
  • Mobile OS
    • BlackBerry: UI Guidelines - BlackBerry Smartphones - Best practice: Implementing shortcut keys
  • Cross-OS environments
    • Eclipse: Eclipse Keyboard Shortcuts
    • Java SE: Java Look and Feel Design Guidelines: Keyboard Operations
    • Lotus Notes: Keyboard shortcuts in Notes 6.x and Notes 7.x

Intent of Success Criterion 2.2.2:

Users need to be able to jump directly to next or previous viewports without having to visit every element in a viewport on the way to the next viewport. Not being able to jump directly can add an exorbitant number of navigation commands to operations that should be easy and efficient. Users need keyboard access to all viewports and enabled elements so that they can manipulate them, view them with screen magnifiers, or have them described by screen readers. The ability to move both forward and backward through the navigation order greatly reduces the number of keystrokes and allows the user to more easily recover from mistakes in overshooting a destination. This navigation can be among applications, windows, or viewports within an application. This includes the user agent's user interface, extensions to the user interface (e.g. add-ons), and content.

Examples for Success Criterion 2.2.2:

• Sooj has a repetitive stress injury and cannot use a mouse, so she moves the keyboard focus to the next pane by pressing F6 or to the previous pane by pressing Shift+F6. She moves between tabbed document views by pressing Ctrl+Tab and Shift+Ctrl+Tab.
• Sooj is working in her web browser, where one document window (viewport) is active (has the active keyboard focus). When she switches to her word processor, the web browser's window and its keyboard focus become inactive, and it hides its cursor. When Sooj switches back to the browser window, it reactivates that viewport, its keyboard focus becomes active again, and its cursor reappears in the same location as when she switched to a different application.
• A developer creates an extension to a user agent that allows the user to add notes about each web page being visited. Sooj presses a shortcut key to move focus to the user interface of this extension and interact with the functionality offered by the extension. Similarly, Sooj presses another key to move focus back to the main viewport for the user agent in the same location as when she moved to the plugin.

Related Resources for Success Criterion 2.2.2:

• 2.2.1 Sequential Navigation Between Elements for background information on the importance of sequential navigation.

Intent of Success Criterion 2.2.3:

When the content author doesn't explicitly define a consistent tab order, the browser will provide one. Users need to have a mental map of where the focus will land when they press the Tab key or use other sequential navigation commands. If the focus jumps in seemingly random fashion, skipping up or down, it becomes impossible to use this method efficiently because users must stop, find the focus, reorient, and determine what direction they should proceed every time they press navigation keys. This is a particular problem for users with some cognitive limitations or whose disability makes input difficult, tiring, or painful. Content authors are expected to define a logical navigation order in their documents, but if they have not, this success criterion ensures that the order will at least be consistent between user agents.

Examples for Success Criterion 2.2.3:

• [mobile] Alec is filling out an HTML form. Because the form's author has not specified a navigation order using the tabindex attribute, when Alec presses the Tab key the focus moves to the next control in the order defined in the underlying HTML. This order is logical as long as the author is not using styles to change the visual order. Alec has the same experience completing this form on his mobile phone.

Related Resources for Success Criterion 2.2.3:

• WCAG 2.0 success criterion 2.4.3 Focus Order

Intent of Success Criterion 2.2.4:

Users need a good mental map of the navigation sequence and behavior, and particularly need to know when they have started over again so they can maintain that mental map and not waste time and energy inadvertently revisiting information. This is a greater problem for users who have limited short-term memory, perceive a narrow field of vision, or use a screen magnifier, screen reader or small screen device. This also prevents people with mobility issues from having to use extra navigation commands.

Examples for Success Criterion 2.2.4:

• Betsy has low vision. She is using a screen magnifier that only shows her a single line of text. She's navigating through a long list of unsorted items in a list box, searching for an entry that she does not realize is not in the list. Each time she presses the down arrow she is presented with the next item in the list. The list box wraps, so after she reads the final entry and presses the down arrow, she is once again presented with the first entry in the list. Unfortunately, it takes her a long time to realize that she's scrolling through the same set of items again and again. To avoid this, she can turn on an option to prevent wrapping, or have the user agent play a sound or display a message to indicate that it is wrapping back to the first item. This behavior should be under the user's control, because keyboard users who can see the entire screen may not want to be interrupted by a pop-up dialog box.
• [mobile] Jeff has a mobility impairment. He uses gestures to navigate the page. When he reaches the last active element on the page there is an indicator that the end of the page is reached before changing focus (e.g. wrapping to the top, switching pages).

Related Resources for Success Criterion 2.2.4:

• None

Intent of Success Criterion 2.3.1:

People who are blind or have mobility problems often find it difficult or impossible to use a mouse to move the viewport to, and focus on, important elements. Some other form of direct navigation – such as numbers or key combinations assigned to important elements – should be available. Direct navigation can be accessed via keyboard, which also supports other forms of input, such as gesture, speech and touch.

Examples for Success Criterion 2.3.1:

• [mobile] Mary cannot use the mouse or keyboard due to a repetitive strain injury. She uses speech input with a mouseless browsing plug-in for her browser. [mobile] She is able to use the same plug-in on her smartphone. The plug-in overlays each link with a number that can then be used to directly select it (e.g. by speaking the command "link 12"). This prevents Mary from having to say "tab" numerous times to select a link.

Related Resources for Success Criterion 2.3.1:

• 2.2.1 Sequential Navigation Between Elements
• 2.5.3 Configure Elements for Structural Navigation
• Mouseless Browsing Firefox Extension

Intent of Success Criterion 2.3.2:

For many users, including those who use the keyboard or an input method such as speech, the keyboard is often a primary method of user agent control. It is important that direct keyboard commands assigned to user agent functionality be discoverable, including in rendered content. If direct commands are not presented in content, many users will not discover them.

Examples for Success Criterion 2.3.2:

• Fiona uses an audio browser. When the system reads form controls in the rendered content, it reads the label of the form followed by the accesskey (e.g. "name alt plus n").
• Mary cannot use the mouse or keyboard. She uses speech input. She is composing an email and wants to attach a file. She sees Ctrl+Shift+A next to the link to attach a file. Mary says the command to add the attachment.
• [mobile] When reading email on her tablet, Mary touches a control which opens a toolbar with a setting to display the accesskeys and other direct commands that the author created. She sees that a 3-finger swipe will delete the current email.

Related Resources for Success Criterion 2.3.2:

• 2.1.5 Follow Text Keyboard Conventions
• Mouseless & More for perceivable navigation and activation keys
• Accesskey shortcuts in Google Chrome and more
• Firefox hack to display "accesskey" keyboard shortcuts

Intent of Success Criterion 2.3.3:

People who are blind or have mobility problems often find it difficult or impossible to use a mouse to move the viewport to, focus on, and activate important elements. Some other form of direct navigation – such as numbers or key combinations assigned to important elements – should be available. Direct navigation can be accessed via keyboard, which also supports other forms of input, such as gesture, speech and touch.

Examples for Success Criterion 2.3.3:

• Mary cannot use the mouse or keyboard due to a repetitive strain injury, instead she uses voice control technology with uses a mouse-less browsing plug-in to her browser. The plug-in overlays each hyperlink with a number that can then be used to directly select it (e.g. by speaking the command "select link twelve"). This prevents Mary from having to say the word 'tab' numerous times to get to her desired hyperlink.
• [mobile] Mary cannot use the mouse or keyboard due to a repetitive strain injury. On her mobile phone, Mary uses a single speech command to launch the app, rather than having to use multiple commands to page through screens to find the app icon and activate it.

Related Resources for Success Criterion 2.3.3:

• Configure Elements for Structural Navigation

Intent of Success Criterion 2.3.4:

For many users, including those who use the keyboard or and input method such as speech, the keyboard is often a primary method of user agent control. It is important that direct keyboard commands assigned to user agent functionality be discoverable as the user is exploring the user agent. If direct commands are not presented in content, many users will not discover them.

Examples for Success Criterion 2.3.4:

• Vlad is a keyboard-only user who uses a browser on the Mac operating system. When he needs to perform a new operation with the browser user interface, he searches for it in the menus, and notices that the menu item has a "⌘" label (e.g. "Copy ⌘+C"). This indicates the direct activation command he can use in the future to avoid having to traverse the menus.
• Amir uses ability switches to control an onscreen keyboard for the Windows operating system. When he presses the "Alt" key the available browser user interface accesskeys are shown as overlays on the appropriate user interface controls (e.g. "File with 'F' in an overlay").
• [mobile] Neta has a repetitive strain injury. She relies on gestures and shortcuts to complete tasks. Using a specialized command on her mobile device, she can pull up an overlay of arrows and text showing all the commands that can be completed in that context. This allows her to learn new programs as efficiently as possible, making it less likely she will overtax her hands.

Related Resources for Success Criterion 2.3.4:

• None

Intent of Success Criterion 2.3.5

People using a keyboard interface need the ability to remap the user agent's keyboard shortcuts in order to avoid keystroke conflicts with assistive technology, reduce number of keystrokes, use familiar keystroke combinations, and optimize keyboard layout (e.g. for one-handed use). This is important for people with dexterity issues where every keystroke can be time consuming, tiring or painful. It is also important for people using assistive technologies such as screen readers, where many keystrokes are already in use by the assistive technology. The goal of this success criterion is to enable the user to be in control of what happens when a given key is pressed, use the keyboard commands that meet specific needs, and save the modifications.

Content authors can use the Accesskey attribute to define shortcut keys that allow quick access to specific elements, actions, or parts of the web content. The author can select shortcuts that are different from what the user expects. Users who rely upon keyboard input may want consistent shortcut keys across the sites they visit.

Users should have the option to make any keyboard shortcuts be persistent across browsing sessions. The user should be able to save, import and export these settings.

User agents can also offer the user the option to automatically apply preferred key combinations for content that has author-specified accesskey bindings that are based on the associated text, label, or ARIA role. This overrides any author-specified keybinding.

Examples for Success Criterion 2.3.5:

• Frank has repetitive strain injuries and uses speech input. He has defined standard commands to access commonly used parts of a website. For example, when Frank says "site search", the cursor jumps to the search field. If the author has assigned an access key that is not standard, Frank can override it and set the access key to a standard mapping so he can say the same search command across all the sites he uses.
• Laura types with one hand and finds keys on the left side of the keyboard easier to press. She browses to a web page and notices that the author has assigned access keys using keys from the right side of the keyboard. She opens a dialog in the user agent and reassigns the access keys from the web page to the left side of the keyboard. She also uses the user agent's preference settings to redefine its keyboard shortcuts in the same way.
• [mobile] Laura types with one hand. On her mobile device, Laura maps common website actions to numeric shortcut keys. For example, she prefers to have the 1 key to activate a site's search function. An author of a site visited daily by this user defines "S" as the accesskey for the search function. Laura overrides the author-specified accesskey of "S" with "1".
• Elaine has low vision and is using a screen magnification program. The program uses Alt+M to increase the size of the magnified area of the screen. She notices that in her web browser, Alt+M is a access key for activating a home button that stops her from being able to control her magnification software. She opens a access key reassignment feature in the user agent, and sets Alt+O to be the new access key for the home button. Her screen magnification software now works correctly.
• George uses a screenreader. The screenreader uses Ctrl+F to read the item with focus. Since this is a common user agent command for Find, the user agent allows George to reassign the Find command to a non-conflicting key binding. The user agent provides a list of user interface features and default keyboard assignments with options for the George to assign new key combinations. George saves the user keyboard customizations the same way he saves other user preferences.

Related Resources for Success Criterion 2.3.5:

• Guideline 2.7 - Configure and store preference settings

Intent of Success Criterion 2.4.1:

The find or text search function in a user agent allows the user to easily locate desired information in rendered content. People who read or navigate slowly or with difficulty due to a disability rely more heavily on the ability to search for text, rather than scanning or reading an entire document to find it. The ability to search alternative content allows screen reader users to find content they heard on their speaker. Users with hearing impairments use Text Search as an efficient method of jumping to specific points in a video. Users who find it difficult to use the mouse or keyboard and have to limit their physical operations will save movements using search.

Examples for Success Criterion 2.4.1:

• Marvin has a dexterity impairment. He needs to move efficiently to specific text in the document.  The user agent provides a local search function that is available using speech commands. Marvin says "find box," a text box with a search button appears. He speaks the word he is looking for, and says "enter", which executes the search function.
• Betty, who has low vision, is attempting to create a user stylesheet for a site. She needs to know the 'class' attribute value for navigation headers. Betty gets the source view of the current page and searches for the specific phrase used in a navigation list to find the class associated with  the navigation element
• Joe, a user with a distraction disorder, is taking an online exam. He is working on the 6th question when he realizes he wrote something wrong in the essay on question 2. He uses the search function in the browser to find the text in error inside the textarea of question 2.
• Sam is a screen reader user. He has images off and the alternative content for images  is revealed. He wants to send the flow chart image on the page to a colleague. Sam searches for the word "flowchart" that he heard spoken as part of the 'alt' text for the image. He then uses the context menu to select the address of the image and sends it to a colleague.
• Agnes is deaf. She is watching a video with captions turned on. Agnes uses the search function to search through the captions and jump to the point in the video where the search term is located in the time line.
• Greta has a reading impairment. She is trying to efficiently locate some information in a large, detailed graphic. She is using a browser with native support for SVG. When Greta searches for a term, text within the SVG is searched along with the HTML content.

Related Resources for Success Criterion 2.4.1:

• None

Intent of Success Criterion 2.4.2:

People who read slowly or with difficulty due to a disability rely more heavily on the ability to search for the text they're looking for, rather than scanning or reading an entire document to find it. Local find in a user agent allows the user to easily locate desired information in rendered content. The ability to search for alternative text content allows screen reader users to find content they heard on their speaker. Users with hearing impairment use text search as an efficient method of jumping to specific points in a video.

Examples for Success Criterion 2.4.2:

• A user has been reading through a web page and wants to quickly locate a phrase previously read. When opening the browser's page search feature, the user has options to search forward and backward from the current location. If the search reaches an endpoint in the document, the user is notified that the search has wrapped around, such as with an alert box or other indication.

Related Resources for Success Criterion 2.4.2:

• None

Intent of Success Criterion 2.4.3:

It is important for the user to easily recognize that a search term has been found and that the term is revealed to the user in context. The user agent moves the viewport to include the found term and the term is highlighted in some fashion.The point of regard is the found element in the viewport. Any subsequent searches on the same term or other navigation tasks (e.g tabbing to the next anchor) begin from this point.

Examples for Success Criterion 2.4.3:

• Jules has low vision and uses a magnified screen. She frequently searches for terms that appear multiple times in a document that contains a lot of repetition. It is important that the viewport moves and if necessary her screen scrolls after each search so she can easily track where she is in the document.

Related Resources for Success Criterion 2.4.3:

• None

Intent of Success Criterion 2.4.4:

It is important for users to get clear, timely feedback so they don't waste time waiting or, worse, issue a command based on a wrong assumption. It is important during a search that users are informed when there is no match or that the search has reached the beginning of the document.

Examples for Success Criterion 2.4.4:

• Dennis uses a screen reader. As soon as he gets a message that there is no match he goes on to search for something else, however, if he does not get a message he wastes time retrying the search to make sure the entire document has been searched.
• Dennis uses a screen reader. When he searches for a word in a web page and the search wraps to the beginning of the page, his computer beeps to alert him that the search has wrapped.

Related Resources for Success Criterion 2.4.4:

• None

Intent of Success Criterion 2.4.5:

Authors frequently provide alternative content to meet web content accessibility guidelines. Users with disabilities may experience this as part of the content. The purpose of this success criteria is to ensure that text search allows users to locate this content, even if it is not visibly rendered.

Examples for Success Criterion 2.4.5:

• Rhonda typically browses the web with images turned off so she sees alternative text rendered in place of images. She visits a favorite website on a friend's computer and wants to find a link to her favorite artist's photo gallery. She searches for the artist's name on her friend's computer. The alt text is not displayed, but the artist's image is highlighted because her 'text search' command has associated the alt text with the image.
• Dennis remembers a phrase in a captioned training movie that he wants to replay. He goes to the web page with the embedded movie. He types in the phrase in the "Find" box and the user agent moves to the point in the movie where the phrase is found.

Related Resources for Success Criterion 2.4.5:

• None

Intent of Success Criterion 2.5.1:

Many users rely on assistive technology to interpret information and convey it in different ways. Sometimes when a user agent displays different pieces of information, it understands relationships between them that can't easily be conveyed through either the DOM or platform accessibility services. This makes it difficult or impossible for assistive technology to infer and interpret those relationships. In these cases the user agent should present those relationships in a simplified way that can be understood by the assistive technology, and by users who have difficulty interpreting complex visual presentations. This is also required when the hierarchy is included in the DOM in a non-standardized fashion (proprietary attributes or distributed extensibility microdata) because such proprietary information would not be useful to assistive technology.

Examples for Success Criterion 2.5.1:

• Armand is blind. His media player uses an XML data structure that describes the genre, artist, album, and track of each audio piece. It displays a column for each category. He can select one entry to filter the contents displayed in the subsequent columns (e.g. an entry in the Artist column causes the Albums and Tracks columns to only show items associated with the selected artist). The user agent understands the hierarchical nature of the columns, but since this hierarchical data cannot be conveyed in the HTML used for presentation, it is not in the DOM for access by his screen reader. When Armand moves the focus to an item in the Tracks column, the user agent updates a static text field that shows the path of genre, artist, and album associated with the track, and Armand can have this field read to him on request or automatically when it updates.

Related Resources for Success Criterion 2.5.1:

• None

Intent of Success Criterion 2.5.2:

Users who find it difficult or impossible to use the mouse require an efficient way to jump among elements without having to navigate through intervening content. Navigating by heading is especially important when scanning a webpage to find a pertinent section. Navigating by table element is especially important when building or reading tables.

Examples for Success Criterion 2.5.2:

• Jamie is blind. When he reads the New York Times he scans the headlines to find interesting stories. To do this he needs a way to go from headline to headline.
• Billie is a paraplegic who uses speech input to write long legal documents. When she is proofing a document she needs to scan each section header. It takes far fewer speech commands to navigate the section headers when she can jump directly to them. Billie also makes extensive use of tables. It takes far fewer speech commands to navigate tables when she can jump directly among elements. Direct navigation to headlines and table elements allows her to do her job without overusing her vocal cords and within required time constraints.
• Celia has short-term memory issues and is easily distracted. When looking for any particular section of the document she finds it easier to scan through headings by jumping from heading to heading rather than having to scan through an entire page of potentially distracting text. Celia also finds it useful to be able to move from a subheading to a major heading and back to orient herself within the context without becoming confused.
• [mobile] Armand is blind. When he uses the speech input to locate a web page on his smartphone, Armand navigates from heading to heading using touch commands.

Related Resources for Success Criterion 2.5.2:

• None

Intent of Success Criterion 2.5.3:

Authors can visually convey relationships between elements by grouping them spatially, or giving them the same coloration or background. Users may not be able to perceive those attributes when using a screen reader, or when strong magnification makes it difficult to make a mental model of the screen layout. In cases like these, the user agent can assist by providing a view of the data that groups elements that that user agent perceives as implying relationships.

Often the user agent will choose by default the elements it considers important for structured navigation. These may not be relevant in all circumstances. For example, the user may wish to navigate via informal mechanisms such as microformats or or by a particular element.

Examples for Success Criterion 2.5.3:

• Fred is blind and wishes to navigate through the menu structure using the Tab key, but the menu is a set of nested list elements with an HTML class attribute denoting the menu-submenu relationship. Because Fred's user agent allows him to configure important elements, he can explicitly include the class name as an important element for navigation. He then assigns a keyboard shortcut to navigate to the next element with the same class name as the element that has the focus.
• [mobile] When Fred is using his smartphone, he selects a control that allows him to change from navigation by heading to navigation by links.

Related Resources for Success Criterion 2.5.3:

• None

Intent of Success Criterion 2.6.1:

Users interacting with a web browser may use one or more input technologies including keyboard, mouse, speech, touch, and gesture. Sometimes a web page is scripted so that it assumes and requires an input method that is not available to the user, such as handling drag events for a user relying solely on the keyboard. In those cases, the user needs to determine what methods are available and activate that element with a modality independent method.

In addition, any one input method should not hold back another. For instance, people who don't use a mouse shouldn't have to map their input methods to the same steps a mouse user would take. The user agent can constrain steps such as not allowing a mouseup before a mousedown.

Examples for Success Criterion 2.6.1:

• Jeremy cannot use a mouse. He needs to activate a flyout menu that appears when he hovers the mouse over a button. He navigates to the button and pulls up its context menu, which includes an "Inputs" submenu that lists the available input methods (e.g. events that were registered for this element: click, double-click, swipe left, and hover). Then he chooses the "Hover" command.
• Ken is a speech input user. In order to get his work done in a reasonable amount of time and without overtaxing his voice he uses a single speech command phrase to move the mouse up, left and click.
• Karen cannot use a mouse. She clicks a single key to activate both events for link that has an onmousedown and an onmouseup event link.
• [mobile] Ingrid has low vision. When navigating a page with a smartphone, she can choose a bluetooth keyboard or gestures to operate all of the controls within the page.

Related Resources for Success Criterion 2.6.1:

• Modality Independent Controls
• 1.3.1 Highlighted Items

Intent of Success Criterion 2.7.1:

When a user has customized settings within the user agent to maximize accessibility, customization is saved between browsing sessions. The user can automatically use those settings in subsequent browsing sessions.

Examples for Success Criterion 2.7.1:

• Lynn has moderately low vision. She sets the default zoom level, font size, and colors to make pages easier for her to read. Because those settings are persistent, she doesn't have to manually restore her settings every time she starts the browser.
• Brian has to adjust settings in his browser to make it fully compatible with his speech input system. It's difficult for him to adjust these settings, since he can't fully operate the browser until it's complete. Once his browser is configured this way, he relies on it staying in that configuration even if he upgrades the browser or restarts his system.
• [mobile] Betty has low vision. She customizes her mobile browser's color and font settings to make text much easier to read. Her browser incorporates a cloud-based profile so she can retain her settings across her browsing sessions and her desktop and tablet browsers.

Related Resources for Success Criterion 2.7.1:

• None

Intent of Success Criterion 2.7.2:

For some users, it may be difficult to easily recall all modified settings. Others may find it difficult to navigate to each modified setting, especially if a particular setting impacts their ability to do so. Users who customize settings may find that their chosen settings are not suitable and decide to restore these settings to default values. This success criteria allows a user to easily restore all preference settings to default values using a single function or action.

Examples for Success Criterion 2.7.2:

• Ron is blind. He accidentally changes a browser setting that makes his browser incompatible with his screen reader, preventing him from changing it back. He restarts his browser using a command line option that starts in the default configuration. From there he can adjust the setting that caused him problems.
• [mobile] Kathy has repetitive stress injuries which makes it painful to experiment with settings. She accidently turns on a zoom feature on her smartphone and cannot figure out how to turn it off. She gestures to navigate to the preferences menus and selects a command to reset preferences to default.

Related Resources for Success Criterion 2.7.2:

• 3.2.5 Settings Change Confirmation

Intent of Success Criterion 2.7.3:

Some users may need to change their setting preferences under circumstances such as varying levels of user fatigue, changes in environmental noise, or changing lighting conditions. Providing an easy method for saving and switching between sets of preferences helps the user complete intended tasks.

Examples for Success Criterion 2.7.3:

• [mobile] Hiroki has low vision. When he is carrying his tablet computer he operates it with the built-in touchscreen. When at his desk he links it to a Bluetooth keyboard and mouse, and redirects the display to a large computer monitor. The browser allows him to quickly switch between different configurations for different environments.
• Davy has moderately low vision and must adjust the contrast of media to different levels for day and night. Because this requires a multiple steps, he has two user profiles, one for each environment.
• Aaron has repetitive strain injury. He usually uses a keyboard and mouse, but when his repetitive strain injury is bothering him he prefers to use the keyboard and avoid using the mouse as much as possible. At those times he uses his browser's user preference profiles to load a different configuration that’s optimized for the keyboard.

Related Resources for Success Criterion 2.7.3:

• None

Intent of Success Criterion 2.7.4:

Users with disabilities may not be able to use a user agent in a particular configuration. This can occur during setup when default settings don't meet their needs, or after someone changes an option. If users cannot change the settings from the user interface, they need a way to adjust or reset those options from outside the user agent. The user agent can accomplish this in multiple ways including detecting and implementing the platform accessibility settings, providing an external file to modify, providing access to settings from a separate utility program, providing accessibility options in the installation program, or providing command-line switches to change the user agent's behavior.

Note: User agents are encouraged to allow all user preferences to be adjusted.

Examples for Success Criterion 2.7.4:

• Aosa is blind. Her web browser is incompatible with her screen reader unless she changes one of the browser's advanced settings. Because she cannot activate and use the appropriate dialog box until the setting is changed, she needs to start the browser using a dedicated command-line switch that changes the behavior.
• Bintu is deaf and enjoys watching captioned videos. Since different video players may not have accessible settings, she sets her browser to always display captions, knowing the video player will respect the browser's request to display captions. In this way the options in one user agent (the embedded video player) are set outside its user interface by being set in another program (the hosting browser).
• Sasha requires high contrast to be able to discriminate the shape of letters. She has set the accessibility preferences on her computer to use high contrast mode. When she launches her browser, it detects that she is using high contrast and adjusts the font and color settings for its user interface to reflect those settings.
• Justin has an attention deficit disorder. He is setting up his new e-book reader and is interrupted while setting the default font colors. He accidentally sets his background and font color to white on white. He can't read the settings screen to recover his default settings, so he exits the reader and follows the instructions on the vendor's website to edit the "settings.ini" file to adjust the colors. He restarts the reader with the corrected color settings.
• [mobile] Jan is easily confused by new interfaces. Using the screen reader capabilities on her mobile phone she changes the interface of the updated browser, then can't figure out how to undo them. She uses an app from the browser developer to reset the browser settings to default.

Related Resources for Success Criterion 2.7.4:

• None

Intent of Success Criterion 2.7.5:

Configuring a user agent may be a complex and time-consuming task. Some users hire assistive technology professional trainers to do their system setup. Users who have spent time customizing accessibility preferences to meet their requirements need to migrate preference setting to other compatible devices. Schools and universities also need to maintain accessibility settings across multiple machines.

Examples for Success Criterion 2.7.5:

• Lori is a rehabilitation specialist who works with clients to customize electronics and assistive technology to their needs. She sets up a new system for Ray, and saves a backup of the accessibility setting for Ray and for herself. She keeps electronic backups of her clients' configurations that she can quickly email to them if they lose their settings.
• Ray is blind and uses a screenreader on his desktop and a voice application on his phone. He sets up web-based email application accessibility preferences on his phone. The preferences are automatically reflected in the desktop version of that web-based email application.
• Trisha is a 4th grader with low vision. When she changes classrooms, she carries a USB stick containing her accessibility settings so she and her teachers do not have to use class time customizing her computer.
• [mobile] Betty is a low vision user and has a highly customized color palette defined in her browser. She saves her customizations to a cloud-based storage service, so her preferences can be transferred to the other desktop and mobile browsers that she uses.

Related Resources for Success Criterion 2.7.5:

• None

Intent of Success Criterion 2.8.1:

The user needs to control which user interface elements are visible and usable, where elements are visually located on the screen, and where elements fall in the navigation order. In some cases adjusting whether an element is visible and usable may involve installing or uninstalling a component — or merely showing or hiding it — depending on the user agent and the specific component.

This can reduce keystrokes, bring buttons into view that are hidden by default or otherwise allow the user to interact with the user agent in a more efficient fashion. Users with dexterity impairments or mobility impairments may have problems making the large movements required to select between non-adjacent controls which they need to use frequently. Similarly, users with low vision may have to move their magnified view-port excessively to see frequently used controls. Enabling these controls to be situated together removes some of the strain faced by these users, and increases productivity as task completion times are decreased.

Examples for Success Criterion 2.8.1:

• Martin accesses the computer by pressing keys with a stick held in his mouth. He gets around the user agent with taps on the tab and arrow keys. The button for printing a web page is the last button on a toolbar. This button requires six presses of a right arrow key. This is the only button Martin uses on the toolbar. Using a preferences dialog, Martin is able to configure this toolbar to only show the Print button, reducing the number of time he must press with his mouthstick.
• [mobile] Laura has one hand. When she holds her mobile phone in her left hand, she must use her thumb to press the controls. She configures her mobile apps so that the toolbars are at the left side or the bottom, so she can reach them.
• Caraway has a repetitive strain injury. She uses speech input. The speech program automatically clicks toolbar items that she speaks. In programs she uses a lot she removes toolbars that she doesn't use in order to reduce the probability that the speech program will interpret text input as a toolbar command and click something Caraway does not intend.
• Zelda has a brain injury that leaves her easily confused. She reorders the toolbars in her web-based word processing and layout programs so that the text color and highlight color icons are in the same order and she can rely on habit to click the correct button no matter what program she is in. Without this ability to reorder she finds herself constantly clicking the wrong button because they are configured differently by default in the different programs.
• Devon is easily distracted. In programs he uses frequently, he removes toolbars he does not use in order to cut down on distractions.
• Sally has memory issues that make it difficult to memorize keyboard shortcuts. She has aligned the keyboard shortcuts in several programs so she doesn't have to memorize as many shortcuts. She reminds herself of keyboard shortcuts by hitting a key that gives her a list of keyboard shortcuts in the current program.
• [mobile] Linda has rheumatoid arthritis and finds it difficult to perform the pinch gesture that's commonly used to zoom on mobile phones. She changes the default gesture for zooming to a gesture she can more easily do. Linda's left hand is less damaged than her right hand. She moves a common control from the right side of the screen to the left side of the screen to make it easier to access with her left hand.
• [mobile] Jennifer is blind. She sometimes configures apps on her friend Linda's mobile phone. When Jennifer picks up Linda's mobile phone, she turns on the built-in voice application so she so she can quickly find her way around Linda's phone. When Jennifer is done, she changes the controls back to Linda's original settings.

Related Resources for Success Criterion 2.8.1:

• WAI-ARIA

Intent of Success Criterion 2.9.1:

People who use assistive technology and those who require more time to read, understand, or act upon content (e.g. individuals with reading disabilities or non-native readers of the presented language) should be able to extend or override any content or author imposed presentation or interaction time limits.

Examples for Success Criterion 2.9.1:

• [@@ needs updating] User closes the Exit command on their web browser, which displays a message box asking if they're sure they want to exit, with a timer saying it will assume yes if they don't respond within 10 seconds. User changes settings in their user options to turn off this timeout.
• Susie reads slowly. When she hovers her mouse over a link to see a pop-up showing the destination of the link, the popup ordinarily disappears after two seconds, which is not enough time for her to read it. She turns off this timeout, allowing her to hover the mouse for as long as she needs to read the text before moving it to allow the pop-up to disappear.

Related Resources for Success Criterion 2.9.1:

• Guidance on Applying WCAG 2.0 to Non-Web Information and Communications Technologies (WCAG2ICT)required behaviors for time limits

Intent of Success Criterion 2.10.1:

Seizures due to photosensitivity can occur when there is a rapid series of general flashing, or a red flash. A potentially harmful flash occurs when there is a pair of significantly opposing changes in luminance. A transition to or from a saturated red is potentially harmful irrespective of luminance.

Examples for Success Criterion 2.10.1:

• Jamie has photosensitive epilepsy. He checks a game website that has just added a flashing red icon to advertise their newest product. Because his browser's default configuration protects him from harmful flashing, the potentially harmful flashing does not occur on his machine.
• Jamie visits a weather web site that uses flashing to indicate a tornado warning. In order to avoid triggering seizures, the flashing is limited to fewer than three times per second, and, to be extra cautious, it is not red.

Related Resources for Success Criterion 2.10.1:

• ITC Guidance Note for Licensees on Flashing Images and Regular Patterns in Television
• WCAG 2.0: 2.3.1 Three Flashes or Below Threshold

Intent of Success Criterion 2.10.2:

Seizures due to photosensitivity can occur when there is a rapid series of general flashing, or a red flash. People who are particularly sensitive to flashing can be harmed by any level of flashing. 2.10.2 has the same effect as 2.10.1, going further to ensure that more sensitive users can traverse the web without potentially harmful effects.

Examples for Success Criterion 2.10.2:

• Alfred has photosensitive epilepsy and is particularly sensitive to flashes. He checks a game website that has just added a flashing red icon to advertise their newest product. His browser's default configuration protects him from all flashing, so the potentially harmful flashing does not occur on his machine.

Related Resources for Success Criterion 2.10.2:

• WCAG 2.0: 2.3.2 Three Flashes
• 2.11.1 Time-Based Media Load-Only
• 2.11.5 Stop/Pause/Resume Time-Based Media

Intent of Success Criterion 2.11.1:

Users who need to avoid signals that may trigger seizures, users who are easily distracted, and users who have difficulty interacting with the controls provided for playing media need to be able to load media in a paused state. The user agent provides a global control that sets a state equivalent to "paused waiting for user interaction" for all recognized media when a page loads. The user has a global option to set autoplay to off or paused until the user activates "play". The user agent provides a visual or auditory indicator that the video is in paused state and needs user interaction to start. This prevents media from playing without explicit request from the user.

When the media is not in the actual document, but rather has been created with document.createElement('audio'), the user agent does not recognize that the media exists and cannot give a visual indication by default. In this case, it is up to the author to provide the controls. See WCAG in resources below.

Examples for Success Criterion 2.11.1:

• Jill is blind. She browses the web using a screen reader to listen to the text of web pages. She navigates to her favorite shopping site and is greeted with trumpets blaring and an announcer shouting "Sale, sale, sale!" The audio is so loud that she can no longer hear the web page content. Jill closes her browser and changes a setting titled Play Audio on Request to yes and visits her shopping site again. This time she can read the content and when she is ready plays the audio and smiles, thinking of the deal's she is about to find.
• Jamie has epilepsy that's triggered by certain types of audio. She sets her browser so content does not play automatically so she can avoid audio that could trigger her epilepsy.
• Kendra has photo-epilepsy. She sets her browser so content does not play automatically so she can avoid flashing content that could trigger her photo epilepsy.

Related Resources for Success Criterion 2.11.1:

• Guideline 2.10 - Help users avoid flashing that could cause seizures.
• HTML5 4.8.10.8 Playing the media resource
• WCAG 2.0 - 1.4.2 Audio Control

Intent of Success Criterion 2.11.2:

Documents that do things automatically when loaded can delay, distract, or interfere with user's ability to continue with a task. Replacing executable content like embedded objects, applets and media with a placeholder tells the user what has been blocked and provides a mechanism (e.g. a play button) for unblocking when the user is ready.

Note: A placeholder should take up the same space as the object it is replacing, so that the presentation doesn't need to be reflowed when the execution is started. However, people using mobile devices or screen enlargers, or those who have difficulty with scroll commands may benefit from having the option of a smaller placeholder.

Examples for Success Criterion 2.11.2:

• Jane has difficulty concentrating. In order to concentrate on the text of a document she hides multimedia content and only triggers execution of that content by clicking on the placeholder.
• Evan is blind. He sets the option in his browser so that when a web page loads it does not automatically run an executable object. This way any or music or speech they play won't interfere with his ability to hear his screen reader. When he is ready to hear it, he navigates to the placeholder and presses the Enter key to activate it.
• [mobile] Evan has configured his mobile phone so that any audio or video file displays a placeholder with a triangle "play" icon. That allows him to control when the audio or video starts.

Related Resources for Success Criterion 2.11.2:

• None

Intent of Success Criterion 2.11.3:

Documents that do things automatically when loaded can delay, distract, or interfere with user's ability to continue with a task. The user needs to be able to specify that executable content (e.g. scripts) be blocked when a document loads, be told which content has been blocked, and be able to selectively execute the content at a later time.

Note: Although some web applications and document may be empty until scripts are run, it is important for users to have this level of control.

Examples for Success Criterion 2.11.3:

• Jane has difficulty concentrating. In order to concentrate on the text of a document she wants to prevent animations, media, or dynamic content from executing until she is ready. An icon on the status bar tells her that scripts have been blocked. She can click on it to select which scripts to run.
• Evan is blind. He sets an option in his browser so that when a web page loads it does not automatically start running scripts that might play sounds that would interfere with his ability to hear his screen reader. An icon on the status bar tells him that scripts have been blocked. He can activate it to select which scripts to run.

Related Resources for Success Criterion 2.11.3:

• None

Intent of Success Criterion 2.11.4:

Users with sensory and cognitive impairments may have difficulty following or understanding spoken audio at the normal playback rate. If users can slow down the audio presentation of speech while maintaining the pitch or frequency characteristics, they are better able to follow the spoken content. Users with learning disabilities may be distracted or otherwise unable to follow complex animations or instructional video. With the presentation slowed, users can better observe the visual events of the animation. User may also want to slow down the media if they are taking notes, and do so slowly because of language or dexterity impairments.

Some users with visual impairments prefer faster speech rate on their screen readers or digital audio book players. The ability to speed up the audio while maintaining pitch allows those users to skim spoken audio without loss of understandability.

Examples for Success Criterion 2.11.4:

• Timo experienced a traumatic brain injury and has difficulty comprehending speech. When listening to episodes of his favorite podcast on the web, he slows down the audio by 50% and is able to understand the interviewer's and guest's question and answer session.
• Anu is a blind university student who has grown up with digital talking book players, and regularly listens to spoken audio at 200% of normal speaking rate. In studying for exams, she reviews the online lecture videos from her History course, adjusting the presentation rate to 200% on the web video player in order to quickly review the material. She slows the presentation to normal rate when she encounters material she needs to review carefully.
• Perttu has a learning disability and requires a longer time to follow instructions. He likes to cook and is watching a cooking demonstration on the web. When the instructions go by too quickly, he slows the video player to half speed.

Related Resources for Success Criterion 2.11.4:

• WAI-ARIA

Intent of Success Criterion 2.11.5:

Users with sensory, attentional, or cognitive impairments may have difficulty understanding multimedia content. When users are able to control the presentation rate of time-based media by stopping, pausing, and resuming, they have enough time to understand or act upon presented content, or to stop potentially distracting or harmful content.

Examples for Success Criterion 2.11.5:

• Adam reads more slowly than average because of his dyslexia. He's watching a video of a lecture. When the video shows slides, he presses the space bar to pause the video so that he can read the text at his own speed. When he's ready to continue, he presses the space bar again to resume the video.
• Angelica can have audio-induced seizures. She uses a website to watch and listen to user-contributed podcasts. When she realizes the level of white noise in a particular soundtrack is likely to trigger a seizure. She quickly clicks on the player's "stop" button (or presses the equivalent keyboard command) and the noise is instantly discontinued.
• Allesandro finds it impossible to ignore visual changes. Unnecessary animations make it very difficult for him to read or interact with other content on the screen. When he's reading an article on a newspaper website and finds an animated advertisement or moving text of a news ticker distracting, he chooses the appropriate command to stop all animations.
• Amaryllis is blind and is listening to streaming audio on a web page. When she responds to an incoming email message she uses a keyboard command to pause the audio, which would otherwise interfere with her ability to hear her screen reader.

Related Resources for Success Criterion 2.11.5:

• WAI-ARIA

Intent of Success Criterion 2.11.6:

Users with sensory, cognitive or attentional impairments may find it difficult to understand or follow time-based media. This success criteria allows users to position within the timebase to review content or to skip content that may be distracting.

Examples for Success Criterion 2.11.6:

• Jared has a print disability that makes it laborious to read text. He is watching a technical training video which will display section objectives or summary questions as text. When the text flashes by too quickly for him to read, he presses a key command to skip back an increment so he can read the text. He pauses the video if more time is required.
• Debbie has difficulty with bright or flashing video. When she encounters a flashing transition in a video, she quickly presses a key command to forward the video past the flashing, then carefully uses the slider to adjust the video back to the start of the next section so she can avoid the flashing material.

Related Resources for Success Criterion 2.11.6:

• WAI-ARIA

Intent of Success Criterion 2.11.7:

Users need to be able to navigate time-based media in ways that are more meaningful than arbitrary time increments.

Examples for Success Criterion 2.11.7:

• Marka is blind. She is listening to a video of an hour-long lecture. The section she is in has technical information that builds on material from an earlier section. A sighted user could pause the video and move the slider back to reach visually distinct content from earlier section. Marka uses a control to skip back section by section until she hears the section title name she wants to review. When she is finished, Marka uses the control to move forward section by section until she hears the title of the original topic.
• Wes has fatigue injury that limits the length of his computer sessions. He stops playback of a training video when he is tired. After resting, he restarts the video and navigates to the scene where he left off.

Related Resources for Success Criterion 2.11.7:

• WAI-ARIA

Intent of Success Criterion 2.11.8:

Users with certain types of low vision need to control contrast and brightness of time-based media so they can discern the content. Users who are prone to seizures need to be able to reduce or dim contrast and brightness to protect themselves from seizures caused by flashing content.

Examples for Success Criterion 2.11.8:

• Frank has albinism. He requires a higher contrast to discern a video image. When Frank is watching an instructional video, he selects a menu item that allows him to increase the contrast of the video. This makes it easier for him to see the important content.
• Kelly has photo-epilepsy and is watching an amateur video taken on a sunny day near the water. Concerned that the video may contain flashing that could trigger a seizure, Kelly selects a menu item of video controls that allow her to reduce the brightness and contrast of the video. While some of the detail is lost, Kelly can safely watch the video.

Related Resources for Success Criterion 2.11.8:

• WAI-ARIA

Intent of Success Criterion 2.12.1:

Some users rely entirely on pointing devices, touch, or gestures, and find these methods more convenient than keyboards. Other users rely on speech input. These users can operate applications more easily and efficiently if they can enter text with their chosen method of input. On systems that support alternative input methods, it is important that the user agent support these utilities.

Examples for Success Criterion 2.12.1:

• Ruth has extremely limited motor control and slurred speech. She operates her computer using a head pointer. Her desktop operating system includes a virtual keyboard utility. When active, the on-screen keyboard reserves the bottom portion of the screen for its own use, so the user agent respects this and does not cover that area even in modes that would normally take up the full screen. The user agent avoids communicating with the hardware keyboard through a low-level system API that would miss virtual keyboard input.
• Randall has repetitive stress injuries that make keyboard and mouse input painful. He carries out most computer operations using speech input, including completing web forms across multiple web sites. His user agent supports the APIs used by 3rd party speech input applications. This allows him to use his chosen input method whereever needed.
• Rick is paralysed from the neck down. He uses eyeblinks to control an onscreen keyboard. His user agent supports the APIs used by 3rd party eye blink applications.

Related Resources for Success Criterion 2.12.1:

• None

Intent of Success Criterion 2.12.2:

Some users rely entirely on pointing devices, touch, or gestures, and find these methods more convenient than keyboards. Other users rely on speech input. These users can operate applications more easily and efficiently if they can navigate and control applications. On systems that support alternative input methods, it is important that the user agent support these utilities.

Examples for Success Criterion 2.12.2:

• Ruth has extremely limited motor control and slurred speech, so operates her computer using a head pointer. The mouse pointer moves in response to the orientation of her head, and she clicks, double clicks, or drags using a sip-and-puff switch. It is much easier for her to point and click on a button or menu item than it is for her to simulate keyboard shortcuts using her on-screen keyboard. In fact, she prefers to customize her applications to make most functions available through toolbar buttons or menu items, even those that are by default available only through keyboard shortcuts.
• [mobile] Randall has repetitive stress injuries. The web browser on his smart phone allows him to perform most operations using speech commands. Unfortunately, a few features are only available through the touchscreen, which Randall finds painful to use. In the next version of the browser, the remaining features are enabled using speech, and Randall finds the product safer and more convenient to use.

Related Resources for Success Criterion 2.12.2:

• Success Criterion 2.12.1 Support Platform Text Input Devices

Intent of Success Criterion 2.12.3:

If the platform does not support text, the user agent provides a mechanism for text input as well as all other input device controls. Some users rely entirely on pointing devices, or find them much more convenient than keyboards. These users can operate applications much more easily and efficiently if they can carry out most operations with the pointing device, and only fall back on a physical or on-screen keyboard as infrequently as possible. If the platform provides the ability to enter arbitrary text using a device (such as large vocabulary speech recognition or an on-screen keyboard utility), the user agent is required to support it per Success Criterion 2.12.1. If the platform does not provide such a feature, the browser is encouraged to provide its own.

Examples for Success Criterion 2.12.3:

• Ruth has extremely limited motor control and slurred speech, so operates her computer using a head pointer. The mouse pointer moves in response to the orientation of her head, and she clicks, double clicks, or drags using a sip-and-puff switch. The operating system does not provide an on-screen keyboard, but in order to be maximally accessible, a small on-screen keyboard is available as an add-on for her browser.
• [mobile] Randall has a web browser on his smart phone that allows him to perform most operations using speech commands. By offloading the speech recognition to an Internet server, it is able to perform large vocabulary speech recognition, so Randall can use his voice to compose email and fill in forms, as well as controlling the browser itself.

Related Resources for Success Criterion 2.12.3:

• None

Intent of Success Criterion 3.1.1:

It's important that users be able to avoid unnecessary messages. Messages designed to inform the user can be a burden to users for whom pressing keys is time-consuming, tiring, or painful. Similarly, users with some cognitive impairments find it difficult to deal with constant distractions caused by updating visual or audio information, and would prefer to hide unnecessary updates.

Examples for Success Criterion 3.1.1:

• Randall has repetitive strain injuries. He finds pop-up messages difficult. Randall has set the option to receive updates only on request. This way, he can request updates when he has a friend helping him, so that if the update changes the way his computer behaves, he can get help to adjust the computer settings or roll the update back.
• Shirley has a cognitive disability and is distracted by the page flicker. A web page has a stock market ticker that is coded as having a WAI-ARIA low priority level, so she changes the browser's preference setting to indicate that regions with low priority level should not be automatically updated.

Related Resources for Success Criterion 3.1.1:

• WAI-ARIA

Intent of Success Criterion 3.2.1:

Users need to be protected against accidentally submitting a form. Some assistive technologies use the Enter key to advance to the next field. If the form is designed to submit on Enter, the user can unknowingly "submit on Enter" function.

Examples for Success Criterion 3.2.1:

• Marka is blind and uses a screenreader. When she installs a web browser she selects an option to disable form submission on Enter. This allows her to complete forms from the banking website knowing that the form won't be submitted until she selects the submit button.
• Ryan uses a mouse but his hand tremor makes him more likely to accidentally miss his intended target. Cancel and Submit (or OK) buttons are often next to each other, and Ryan has found that submitting a form inappropriately can cause serious complications, so he sets a browser option to always request confirmation of form submissions. As a result, when he clicks on a submit button the browser presents a message box asking "Are you sure you want to submit this form?" with larger, well-spaced buttons for Submit and Cancel.

Related Resources for Success Criterion 3.2.1:

• 2.1.1 Keyboard Operation
• 3.2.4 Text Entry Undo

Intent of Success Criterion 3.2.2:

Retracing a navigation step is important for users with cognitive issues that involve memory and attention. This is also important for users whose means of input is not 100% accurate, such as speech input users or users with fine motor challenges. It is also beneficial for users for whom navigation is time consuming, tiring, or painful, because it allows them to avoid having to re-enter long URLs.

Examples for Success Criterion 3.2.2:

• Joe is a quadraplegic who is using speech input in a relatively noisy room. The program hears an especially loud word from across the room and interprets it as Joe saying "Enter" to click a selected link. Joe says "Go Back" to go back to the page he was on.
• Mike's head injury leaves him easily distracted. He is in the middle of a search when the phone rings. When he comes back he says "Go Back" to go back to the original search page so he can reorient himself.
• Ellen had a head injury that affects her short-term memory. She clicks on a link, and is interrupted by a colleague. When she goes back to her task she has forgotten what she was originally doing. It's important that she be able to retrace her steps to reorient herself.
• Etta has moderately low vision and doesn't use assistive technology. She occasionally clicks on the wrong link. When she does so, she clicks the Back button in order to get back to where she had been.

Related Resources for Success Criterion 3.2.2:

• 1.8.10 Provide Viewport History

Intent of Success Criterion 3.2.3:

Users with various disabilities benefit from spell checkers. The ability to check spelling is particularly important for users with disabilities such as dyslexia that significantly increase the likelihood of misspelled words. Spellcheckers also alert blind and low vision users to errors in text entry.

Examples for Success Criterion 3.2.3:

• Amanda is dyslexic and frequently spells words incorrectly. She is able to correct words when alerted to the errors. She navigates to her web-based email application and composes a new message. The user agent alerts her to spelling errors as she is typing and she quickly corrects the mistakes and sends an error-free message.

Related Resources for Success Criterion 3.2.3:

• None

Intent of Success Criterion 3.2.4:

Users who are blind, have visual impairments, or have cognitive disabilities may have difficulty determining the location of the keyboard focus. This puts them at risk of entering text in an undesired window or location. Users with mobility problems may have difficulty selecting a form field and may not notice an incorrect selection until they have entered text information.  These users need to be able to reverse a text entry ("Undo") prior to submission.

Examples for Success Criterion 3.2.4:

• Billie is a paraplegic who uses speech input. When she is working from the main office, she is in a noisy location that can interfere with her speech input.  She is writing a blog entry and is almost finished when her speech input software incorrectly interprets some background noise as a "select all" command. This causes her to overwrite her entire blog entry with the next phrase she utters. She then uses the "undo" command to reverse the text entry and restore her blog entry.
• George is blind and uses a screenreader.  He is entering financial information into his banking billpaying account.  He types the first few letters of the payee from a long list. When George reviews the selection prior to pressing "submit", he hears that he had selected the wrong payee. George uses the "undo" command and selects the correct payee.

Related Resources for Success Criterion 3.2.4:

• None

Intent of Success Criterion 3.2.5:

The description of some user interface settings can be confusing to less technical users. Settings changes can also have unintended consequences. In addition, some disabilities make it more likely that a user can make an unintended selection on a preference screen.  Users need to be able to reverse changes to the user interface.

Examples for Success Criterion 3.2.5:

• [mobile] Davy has moderately low vision. He is adjusting the contrast of the background on his mobile phone when he accidentally selects a white background with the previously selected white text. This causes all the icon labels to disappear.  He can see a highlighted rectangle on the screen that usually contains the word "undo" when he makes a change on his phone. He selects that box and the dark background returns, so he can now read the text.  He then changes the background to a color with sufficient contrast for comfortable reading.

Related Resources for Success Criterion 3.2.5:

• Guideline 2.7 - Configure and store preference settings

Intent of Success Criterion 3.2.6:

Users need to know that their actions are producing results even if there is a time delay. Users with limited ability to interact with a device need a passive indicator of progress. Users who cannot see visual indications need to have feedback indicating a time delay and have an idea of where they are in the retrieval process. This reduces errors and unnecessary duplicate actions.

Examples for Success Criterion 3.2.6:

• Larry has severe repetitive strain injuries and is limited to typing for only a short period of time every day. He downloads a long document, in which he wants to search. He periodically checks the progress bar to make sure it is fully downloaded before running his search.
• Jennifer is blind and uses a screen reader. She clicks on a link that is downloading a large file. The user agent displays a programmatically available progress bar. If the progress stops, the user agent displays a message that it has timed out.
• Jennifer purchases an item from a online shopping cart and is waiting for confirmation. The user agent displays a programmatically available message that it is waiting for a response from the server. If the process times out, the user agent displays a message that the purchase has timed out.

Related Resources for Success Criterion 3.2.6:

• 4.1.6 Expose Accessible Properties

Intent of Success Criterion 3.3.1:

People with disabilities need documentation in a format that is accessible. If provided as web content, it must at least conform to WCAG 2.0 level "A." If the document is not provided as web content, it must be in conformance to a published accessibility benchmark.

Examples for Success Criterion 3.3.1:

• Randall has repetitive strain injuries. His injuries make it painful to sit at the computer for long periods of time. When exploring a new program, he will often print out the documentation to read while away from his desk.This allows him to be more efficient, and learn new programs without having to spend as much computer time.
• Lee has low vision. When she upgrades her user agent, she wants to see if any features she relies on have changed. She opens the HTML help documentation and pleased to see that the documentation is using her preferred settings.

Related Resources for Success Criterion 3.3.1:

• None

Intent of Success Criterion 3.3.2:

Some users with disabilities will need help in determining how to use the accessibility features that user agents provide. There are four possibilities:

1. This information is provided in the documentation of the user agent (e.g. help system, context sensitive help, etc.);
2. The user interface element is self-explanatory (e.g. a zoom % drop-down menu);
3. The accessibility feature is actually a service of the platform (e.g. high contrast mode), which therefore has the responsibility to document the feature; or
4. The feature is not used directly by users (e.g., passing information to a platform accessibility service). In this case, user documentation is not required, although developer documentation (e.g. how accessibility APIs are used, the user agent's own plug-in API) would still be recommended.
   

Examples for Success Criterion 3.3.2:

• Lee has low vision. When she installs a new user agent, she checks the accessibility documentation to see if the features she needs are available. She finds section entitled "Browser Features Supporting Accessibility", which provides a detailed description of user agent features that provide accessibility, describes how they function, and lists any supported third party assistive technologies that may be supported or required.
• Lee is exploring the menus of her user agent and finds a feature named "Use My Style Sheet". She clicks "help" to learn that this feature allows custom CSS stylesheets to be created to help make web content more accessible.
• [mobile] Neta has a repetitive strain injury. She relies on gestures and shortcuts to complete tasks. Using a specialized command, she pulls up a list of all the gesture commands available including descriptions.

Related Resources for Success Criterion 3.3.2:

• 3.3.4 Centralized View

Intent of Success Criterion 3.3.3:

Users need to be informed about accessibility features implemented in new versions of the user agent.

Examples for Success Criterion 3.3.3:

• Martha goes to an app store on her computer and installs an update for her web browser. After it installs, she sees a welcome page describing the new features in this release. One of the welcome page links is titled "What's New For Accessibility". Following this link, Martha reads about the accessibility improvements and discovers a feature that allows her to have tooltips displayed for elements when she is using caret browsing. The text also informs Martha that this feature is off by default and that she should go to accessibility settings to turn it on.

Related Resources for Success Criterion 3.3.3:

• None

Intent of Success Criterion 3.3.4:

Users need to know about accessibility features and how to operate them. A centralized view of accessibility features makes it easier for people with disabilities and people who are evaluating software to quickly become familiar with the features such as keyboard shortcuts, how to zoom the viewport, and where to find accessibility configuration settings. Nested user agents or add-ons may provide separate centralized documentation. It is also useful to document accessibility features in context (such as displaying keyboard shortcuts next to their menu command).

Examples for Success Criterion 3.3.4:

• [mobile] Bob is blind and uses a screen reader that is part of his phone's operating system. He downloads a new web browser on his mobile phone. The browser's online help includes a section on accessibility that point him to pages on non-visual access, such as interaction with screen readers, helpful hints such as an explanation of the screen layout, and a list of supported touch gestures.
• Marissa is assessing new user agents for clients who are blind. The first thing she does in looking at each user agent is to turn to the section in the documentation (local or online) that details accessibility features. This gives her a quick overview of the accessibility features across different products.

Related Resources for Success Criterion 3.3.4:

• None

Intent of Success Criterion 3.4.1:

Users need to know that navigation in a web page is going to start in a predictable location and move in a predictable fashion. If a page moves the initial focus to somewhere other than the beginning of the page, the user may skip over content without realizing it. If the focus moves and remains unnoticed, users can make unintentional changes, such as entering data in an incorrect field. Focus changes can cause a window to scroll unexpectedly, confusing users. This is particularly problematic for users who can only see a small portion of the document, because they must use more effort to determine where the cursor has moved. Such users also are more likely to continue typing, not immediately realizing that the context has changed. Users who find navigation time consuming, tiring, or painful (including those using screen readers or with impaired dexterity) may also need more steps to return to the area where they want to work. It may improve accessibility for some users on some pages to have the page set focus to specific links or fields when the page loads, but this can be detrimental for other users, and therefore users need to control this behavior.

Examples for Success Criterion 3.4.1:

• Jerome has repetitive strain injuries. He tries to limit the number of keyboard and mouse entries he makes each day, because it is painful. He loads a page that has its default focus in a search box. Jerome wants to read the content of the page, rather than search. This requires him to make additional clicks to get to the content of the page. He intends to use this page frequently, so he adjusts his browser's settings to disable the automatic focus change to prevent the extra clicking in the future.
• Jessica uses a screen enlarger. She loads a page that contains instructions followed by a form. If the page automatically moves the keyboard focus to the form, she may not realize there were instructions. To avoid this problem, she sets an option to prevent default focus changes.
• James uses speech recognition. He speaks his credit card number by saying several digits followed by speaking "tab". He needs to know ahead of time whether it is necessary to include the "tab" command in the phrase.
• Joey is blind and uses a screenreader. She is filling in a web form that asks for her phone number using three separate fields. When she types the three digits of her area code into the first field, the browser automatically moves the focus to the second field. Because Joey does not realize that the focus has moved for her, she presses the Tab key to move it manually, not realizing that this now puts the focus on the third field rather than the second. To avoid this problem, Joey goes to her browser's Preferences dialog box and checks the option that prevents focus changes that she has not explicitly requested.
• Justine has trouble using a mouse. She uses a keyboard macro in her web email program to execute a command to start a new message and put a block of text in the new message. The focus moves without her control, causing the macro to execute in the Inbox instead of the Compose window. With the Inbox in focus several single-key shortcuts execute, changing the column sorting and deleting several messages.

Related Resources for Success Criterion 3.4.1:

• 1.3.1 Highlighted Items
• 1.8.11 Allow Top-Level Viewport Open on Request
• 1.8.12 Allow Top-Level Viewport Focus Control

Intent of Success Criterion 4.1.1:

Platform accessibility services provide common functionality across the well-behaved applications running on the platform. This reduces exceptions that assistive technology has to implement for the hundreds of applications it may need to support. Most major operating environments provide platform accessibility services that allow applications to work with assistive technologies. These platform accessibility services must be supported by both the user agent and the assistive technology. Specifics of what constitutes a platform accessibility service will differ on each platform, but basic features common to these services are addressed by other success criteria under Guideline 4.1.

Most web-based user agents support this requirement automatically because they run inside host user agents. The host is responsible for exposing all content, including nested user agents, via platform accessibility services. As long as the nested user agent's user interface is entirely web-based and complies with Web Content Accessibility Guidelines (e.g. providing alternative text and supporting WAI-ARIA where needed) the host will understand it well enough to provide a bridge between the content and platform accessibility services.

Examples for Success Criterion 4.1.1:

• Jamie is blind and uses a screenreader. He is testing a new type of button bar for a browser. When coding the new component, the developer supported the relevant platform accessibility services so that Jamie's screenreader can recognize it as a toolbar, and Jamie can identify, navigate, and activate the bar and its buttons.

Related Resources for Success Criterion 4.1.1:

• 4.1.2 Name, Role, State, Value, Description and 4.1.6 Expose Accessible Properties for specific information that should be exposed through platform accessibility services.
• Microsoft Active Accessibility (MSAA)
• Microsoft UI Automation
• Gnome Accessibility Toolkit (ATK)
• GNOME Accessibility Architecture (ATK and AT-SPI)
• Accessibility Programming Guidelines for Mac
• Accessibility Programming Guide for iOS
• Iaccessible2
• Open Source Accessibility for Windows
• Accessibility API Cross reference

Intent of Success Criterion 4.1.2:

Modern web content is highly interactive. Including people who use assistive technology in the interactive experience requires that the user agent provide information about user interface components in a standardized manner.This information includes:

• Name (component name)
• Role (purpose, such as alert, button, checkbox)
• State (current status, such as busy, disabled, hidden)
• Value (information associated with the component such as, the data in a text box, the position number of a slider, the date in a calendar widget)
• Focus (has focus, focusable)
• Selection (selected, selectable)

Every component developed for the user agent must pass this information to the appropriate accessibility platform architecture or application program interface (API). Embedded user agents, like media players can pass Name, Role, State, and Value via the WAI-ARIA techniques. Since not every element supports every property, follow the platform accessibility services convention for cases where an element type does not support one of the listed properties.

Examples for Success Criterion 4.1.2:

• Jamie is blind and uses a screenreader. He adjusts the volume on a web site media player using a slider control. This is easy for him to do because the developer has coded the slider component with WAI-ARIA techniques to pass the following information to the accessibility API:
  Name: Volume control
  Role: Slider
  States & Values:
  • aria-valuenow is the slider’s current value.
  • aria-value-min is the minimum of the volume range
  • aria-value-max is the maximum of the volume range

Related Resources for Success Criterion 4.1.2:

• http://msdn.microsoft.com/en-us/library/ms697187
• http://www.mozilla.org/access/windows/msaa-server

Intent of Success Criterion 4.1.3:

Like everyone else, users who rely on assistive technology need to be able to carry out all tasks provided by the user agent. When a particular user interface component cannot support the platform accessibility service, and thus can't be made compatible with assistive technology, the user agent should let the user achieve the same goal using another component that is fully accessible.

Examples for Success Criterion 4.1.3:

• [mobile] Doug uses a mouse-stick on his smart phone. He uses the assistive touch option on his mobile phone to control an app for 3D design drawing. The app provides a single, complex control for 3-dimensional manipulation of a virtual object. This custom control cannot be represented in the platform accessibility service, so the app provides Doug the option to achieve the same functionality through an alternate user interface: a panel that adjusts the yar, spin, and roll independently using arrow keys.

Related Resources for Success Criterion 4.1.3:

• None

Intent of Success Criterion 4.1.4:

Assistive technologies need all possible information. Applications such as user agents and assistive technologies use a combination of DOMs, accessibility Application Programming Interfaces (API), native platform APIs, and hard-coded heuristics to provide an accessible user interface and accessible content. It is the user agent's responsibility to expose the DOM to assistive technology which in many cases is the richest source of information on web content.

Examples for Success Criterion 4.1.4:

• Joey is blind and uses a screenreader. He is reading a long technical article where code samples are labeled using CSS. In the past, he has had trouble reading technical articles because the CSS text is not exposed to the the platform accessibility API, and is therefore missing from his text. His new browser exposes the CSS DOM information to the platform accessibility services. This allows him to read and search on all of the code sample labels.
  
• Joey is reading a compound document containing HTML, MathML, and SVG. Each has a separate DOM. As Joey moves through the document, he is moving through multiple DOMs. He has no trouble reading it because the transition between DOMs is seamless and transparent.

Related Resources for Success Criterion 4.1.4:

• www.w3.org/TR/SVG/svgdom.html
• www.w3.org/TR/MathML/chapter8.html
• www.w3.org/TR/DOM-Level-2-HTML/
• www.w3.org/TR/DOM-Level-2-Style/
• Gecko DOM Reference
• http://developer.apple.com/mac/library/documentation/AppleApplications/Conceptual/SafariJSProgTopics/Tasks/DOM.html
• http://msdn.microsoft.com/en-us/library/ms533050%28VS.85%29.aspx
• www.adobe.com/devnet/acrobat/pdfs/access.pdf
• www.w3.org/2004/CDF/
• dev.w3.org/2006/cdf/cdi-framework/
• www.w3.org/TR/CDR/
• http://accessibility.linuxfoundation.org/a11yspecs/atspi/adoc/a11y-dom-apis.html

Intent of Success Criterion 4.1.5:

If users can control the user interface using any form of input, they can control it through programmatic access. It is often more reliable for assistive technology to use the programmatic method of access versus attempting to simulate mouse or keyboard input.

Examples for Success Criterion 4.1.5:

• Billie is a quadrapalagic who uses speech input. When she says "Volume 35" her speech input utility programmatically sets the value of the volume slider to 35%. This allows Billie to set the volume in a single command to a specific value rather than simulating mouse clicks.
• Billie uses a direct speech command to set the value of a check box in the user agent preference settings to block pop up windows. Even though the control cycles through “checked”, and “unchecked” using the spacebar or mouse, the speech command uses a programatic command to check the box regardless of whether the box is already checked.

Related Resources for Success Criterion 4.1.5:

• None

Intent of Success Criterion 4.1.6:

These properties are used by assistive technology to create alternative views of the user agent user interface and rendered content. They also provide alternative means for the user to interact with these items. These properties are exposed in the user agent user interface (e.g. menus and dialog boxes) and to recognized aspects of the user content (e.g. HTML script using ARIA to indicate focus on custom controls). Keyboard commands include direct keyboard commands (e.g. Control-f to select the find box) and keyboard sequences (e.g. Alternate-f, to call up the File menu and select Save As).

Examples for Success Criterion 4.1.6:

• Kiara is blind and uses a screenreader. She loads a new version of a popular web browser for the first time. She puts her screen reader into "explore mode", which lets her review what appears on the screen. Using this mode, she identifies the menu bar because her screen reader uses the bounding rectangle of each element to identify that those items all appear on the same horizontal line below the window's title bar.
• Kiara is using a screen reader at her job at a telephone call center. She needs to know the caller name and banking status to immediately respond to each customer appropriately. The web application displays caller names in different colors to indicate banking status, instead of indicating the status semantically (which would be more accessible). However, Kiara's browser exposes the font color to her screenreader, which reads her the customer name followed by the banking status color.
• Max uses a screen magnifier that shows him only a small amount of screen. Because his browser exposes accessible properties to his screen magnifier, he can pan through different portions of a web page and quickly pan back to positions of interest, such as the text matched by a recent Search operation, text that he previously selected by dragging the mouse, or the text caret rather than having to manually pan through the document searching for them.

Related Resources for Success Criterion 4.1.6:

• None

Intent of Success Criterion 4.1.7:

Conveying information for accessibility may involve communication between a user agent, an accessibility API, document object model, assistive technology and end user interaction. The goal of this success criterion is that when interacting with a user agent, the end user perceives the same amount of delay as someone who is not using assistive technology.

Examples for Success Criterion 4.1.7:

• Bonita has polio. She accesses her web browser with a speech input program. She navigates to a web page and speaks the name of a link she wants to click. The link is activated with the same speed as it would be if a mouse had been used to click the link.
• Arthur is blind. He is browsing a web page with a screen reader. As he tabs from link to link, the text of each link promptly appears on his braille display.

Related Resources for Success Criterion 4.1.7:

• None

Intent of Success Criterion 5.1.1:

User agent user interfaces that are web based must meet the same accessibility guidelines as web content. The Web Content Accessibility Guidelines (WCAG) 2.0 are an internationally accepted guideline for accessible web content.

Examples for Success Criterion 5.1.1:

• Lee has low vision. She needs to customize the appearance of her web based media player. WCAG 2.0 success criteria 2.7.1 requires that a user agent enable a user to change settings that impact accessibility. Her web-based media player enables her to change accessibility settings to display high contrast captions.

Related Resources for Success Criterion 5.1.1:

• WAI-ARIA 1.0 User Agent Implementation Guide
• W3C Web Design and Applications Activity
• WCAG 2.0

Intent of Success Criterion 5.1.2:

Most content specifications include features important to users with disabilities. Users may find it difficult or impossible to use a product that fails to support those features. Most content specifications include features important to users with disabilities. Users may find it difficult or impossible to use a product that fails to support those features. Conformance claim documents list the technologies that the user agent fully supports, such as WAI-ARIA, so that users can make informed decisions about whether or not they will be able to use, and therefore should install, a new product or version of that product.

Examples for Success Criterion 5.1.2:

• Jordy is blind and uses a screenreader. He often uses a website that is coded with WAI-ARIA to identify the functions of custom controls. He is downloading a new version of a web browser. If the browser doesn't support WAI-ARIA and expose that information to assistive technology, the website would be unusable. Before he installs the new browser, Jordy makes sure it fully supports WAI-ARIA. He determines this by reading product documentation and UAAG conformance claims posted on the web.

Related Resources for Success Criterion 5.1.2:

• [WCAG20]
• HTML- - listing of the HTML documents
• CSS - listing of the CSS documents
• WAI-ARIA Suite Overview

Intent of Success Criterion 5.1.3:

User agent user interfaces that are not web applications need to be accessible to people with disabilities. Accessibility guidelines already exist for many platforms. Most operating systems have conventions and expectations that aid accessibility, such as keyboard behavior, support of an accessibility API, user interface design. User agents need to comply with the basic accessibility requirements of the platform in use. Developers have the flexibility to conform with the appropriate accessibility guidelines or legislation for their platform or markets.

The user should be able to easily discover detailed information about the user agent's adherence to accessibility standards, platform standards such as MSAA or JAA, and third-party standards such as ISO 9241-171, and should be able to do so without installing and testing the accessibility features.

Note: In the conformance claim, list the requirements you fully comply with, list the requirements you partially comply with and explain, and list the requirements you do not comply with and explain. Where applicable, these explanations can be general and cover several sections at once.

Examples for Success Criterion 5.1.3:

• Lee has low vision and uses a screen magnifier on a Linux system. She loads a new Gnome application that works with her screen magnifier because the developer followed the Gnome Accessibility Developers Guide. For example, the Keyboard Focus section states: "Show current input focus clearly at all times. Remember that in controls that include a scrolling element, it is not always sufficient to highlight just the selected element inside that scrolling area, as it may not be visible. " Lee can use this app because it conforms to this accessibility guideline for focus.
• [mobile] Martin uses a mouth stick to control his mobile browser. Even though he cannot use a pinch gesture, he controls the zoom in his mobile browser with a custom gesture. He can do this because the app developer followed the guidance provided in the "Accessibility Programming Guide for iOS".
  

Related Resources for Success Criterion 5.1.3:

[APPLE-ACCESS]

"Introduction to Accessibility Overview," Apple Computer Inc.

[CARBON-ACCESS]

"Introduction to Accessibility Programming Guidelines for Carbon," Apple Corporation.

[COCOA-ACCESS]

"Introduction to Accessibility Programming Guidelines for Cocoa," Apple Corporation.

[EITAAC]

"EITAAC Desktop Software standards," Electronic Information Technology Access Advisory (EITAAC) Committee.

[GNOME-ACCESS]

"GNOME Accessibility for Developers," C. Benson, B. Cameron, B. Haneman, S. Snider, P. O'Briain, The GNOME Accessibility Project.

[GNOME-API]

"Gnome Accessibility Toolkit API"

[GNOME-KDE-KEYS]

"Gnome/KDE Keyboard Shortcuts," Novell Corporation.

[IBM-ACCESS]

"Software Accessibility," IBM Special Needs Systems.

[IEC-4WD]

IEC/4WD 61966-2-1: Colour Measurement and Management in Multimedia Systems and Equipment - Part 2.1: Default Colour Space - sRGB. May 5, 1998.

[ISO-TS-16071]

"Ergonomics of human-system interaction -- Guidance on accessibility for human-computer interfaces". International Organization for Standardization.

[JAVA-ACCESS]

"IBM Guidelines for Writing Accessible Applications Using 100% Pure Java," R. Schwerdtfeger, IBM Special Needs Systems.

[JAVA-API]

" Java Accessibility Package"

[JAVA-CHECKLIST]

"Java Accessibility Guidelines and Checklist," IBM Special Needs Systems.

[MACOSX-KEYS]

"Mac OS X keyboard shortcuts," Apple Corporation.

[MS-ENABLE]

"Designing Accessible Applications," Microsoft Corporation.

[MS-WIN7-ACCESS]

"Engineering Software For Accessibility", Microsoft Corporation.

[MS-KEYS]

"Keyboard shortcuts for Windows," Microsoft Corporation.

[NOTES-ACCESS]

"Lotus Notes application accessibility," IBM Corporation.

[ORACLE-DESIGN]

"Designing for Accessibility," Eric Bergman and Earl Johnson. This paper discusses specific disabilities including those related to hearing, vision, and cognitive function.

[Editors' Note: Resource links from Jim - compare and expand]

http://www.microsoft.com/windowsxp/using/accessibility/default.mspx

http://www.apple.com/accessibility/

http://www.linux.org/docs/ldp/howto/Accessibility-HOWTO/linuxos.html

http://www.linuxfoundation.org/collaborate/workgroups/accessibility/iaccessible2

http://developer.apple.com/ue/accessibility/

http://msdn.microsoft.com/en-us/library/dd373592%28VS.85%29.aspx

http://msdn.microsoft.com/en-us/windows/ee815673.aspx

Intent of Success Criterion 5.1.5:

When accessing media or specialized content (e.g. MathML) on the web, users with disabilities may have a richer or more accessible experience using a third-party application, plug-in, or extension, rather than using the browser's built-in facilities. Users need to be able to enable or activate a browser plug-in or extension to interact with the content. Alternately, they may elect to save that content to disk and launch it in a third-party application. If streaming video cannot be saved to disk, the browser launches the external viewer, passing it the URI to the online video.

Examples for Success Criterion 5.1.5:

• George is blind. His browser supports the VIDEO tag and adds its own play and pause controls, but George prefers to view the video content in a third-party application that provides much more sophisticated navigation controls such as bookmarks, skip-forward and backwards, and the ability to speed playback without increasing pitch of the audio track. In the browser, he right-clicks on the video to display a context menu, and from that chooses "Open in…", and then chooses his preferred video player. The browser launches the player to show that video file.
• Jukka is blind and uses a screenreader. He is a scientist whose uses mathematical models. Many of the journals he reads online use MathML to display equations. Jukka finds the native support for MathML accessibility in his web browser to be generally compatible with his screen reader, but it can become unreliable for extremely complex equations. In those cases, Jukka selects an alternate rendering plugin to make the MathML understandable to his screen reader.
  

Related Resources for Success Criterion 5.1.5:

• None

Intent of Success Criterion 5.1.6:

People who use assistive technologies such as screen readers may find that a technology isn't fully compatible with a web browser, or that the content authored to meet WCAG still is not accessible when rendered in the browser. This causes information loss and inconvenience. When this happens, users benefit from being able to easily file a report with the user agent vendor to report the incompatibility, similar to the way users can file bug reports or provide feedback.

Examples for Success Criterion 5.1.6:

• Alice is a visually impaired college student who frequently uses a refreshable braille display with her web browser. She experiences difficulty with a drop-down list boxes because the text is only partially rendered on her braille display. When Alice notices this incompatibility, she navigates to the feedback section of her browser. After providing some basic information (such as AT software and computer hardware used), Alice describes the problem and submits the report to the browser vendor.
• Fred has low vision and uses screen magnification software to enlarge displayed information and alter color contrast. While reading content on a website in compliance with WCAG, Fred discovers that the scroll bars are not visible and he cannot scroll further down the page. Unable to read the information he needs, Fred selects the Feedback option from his browser's Tools menu, and is presented with a dialog where he can select which information to transmit to the browser vendor. He includes the current URI of the page he is trying to view, system information including OS and screen magnifier version, and enters a description of the problem he is having. Though not required, Fred chooses to provide his email address so that the vendor may contact him for further details or to provide a workaround.

Related Resources for Success Criterion 5.1.6:

• None