Accessibility

Bypass Blocks> Bypass Blocks # A mechanism is available to bypass blocks of content that are repeated on multiple web pages. Content/Design Considerations Identify the repetitive content on pages and the location of where a skip mechanism should land.

Timing Adjustable> Timing Adjustable # For each time limit that is set by the content, at least ONE of the following is true: Turn off: The user is allowed to turn off the time limit before encountering it; or Adjust: The user is allowed to adjust the time limit before encountering it over a wide range that is at least ten times the length of the default setting; or Extend: The user is warned before time expires and given at least 20 seconds to extend the time limit with a simple action (for example, “press the space bar”), and the user is allowed to extend the time limit at least ten times; or Real-time Exception: The time limit is a required part of a real-time event (for example, an auction), and no alternative to the time limit is possible; or Essential Exception: The time limit is essential and extending it would invalidate the activity; or 20 Hour Exception: The time limit is longer than 20 hours.

Captions (Prerecorded)> Captions (Prerecorded) # Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such.

Color tools> Color tools # WebAIM color contrast checker compares two hex colors and tells you whether they meet WCAG AA and AAA contrast thresholds. Snook’s color contrast analyzer lets you adjust RGB and HSV values and reports contrast compliance interactively.

Poor color contrast. People with limited vision or color blindness cannot read text if there is not enough contrast between the text and background (for example, light gray text on a light-colored background).

Hiding content is very useful for accessibility. We can hide things visually and only display it to screen reader users, we can hide content from screen reader users and only show it visually, or we can hide content from both.

Non-Text Content – Meaningful Images> Non-Text Content – Meaningful Images # All non-text content that is presented to the user has a text alternative that serves the equivalent purpose. Content owners are the best resource for text descriptions since they know what information they want the image to convey.

18F Accessibility Guide: a comprehensive accessibility guide with resources published by 18F, a digital services agency under the General Services Administration (GSA). Accessibility is one of the most important aspects of modern web development.

Page Titled> Page Titled # Web pages have titles that describe topic or purpose. Content/Design Considerations Provide a descriptive title for each page or screen. If the page is a result of a user action or scripted change of context, the TITLE should describe the result of change of context.

When using iframes, it’s important that all content contained in them is accessible. Testing> Testing # Identify all iframes on a page. Using the keyboard, navigate to each iframe to ensure content is accessible.

When using images on a page, you must provide an alternate method for that content. This can be provided in multiple ways. You can provide this information with a caption, alt attribute (alt tag), title attribute, or aria-label attribute.

When tables are used to show data, the header cells that relate to the data cells need to be programmatically linked. This makes table navigation for screen readers more accurate and meaningful.

In content implemented using markup languages, elements have complete start and end tags, elements are nested according to their specifications, elements do not contain duplicate attributes, and any IDs are unique, except where the specifications allow these features.

Cascading style sheets ( CSS) allow us to add and manage styles (e.g., fonts, colors, size, spacing) on web pages. CSS dependence refers to sites that rely on CSS to be functional or understandable.

Inaccessible web content means that people with disabilities are denied equal access to information. An inaccessible website can exclude people just as much as steps at an entrance to a physical location.

Name, Role, Value> Name, Role, Value # For all user interface components (including, but not limited to, form elements, links, and components generated by scripts), the name and role can be programmatically determined; states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies (Level A).

Audio-only and Video-only (Prerecorded)> Audio-only and Video-only (Prerecorded) # For prerecorded audio-only and prerecorded video-only media, the following are true, except when the audio or video is a media alternative for text and is clearly labeled as such:

Headings and Labels> Headings and Labels # Headings and labels describe topic or purpose. (Level AA). Refer to WebAIM’s Using Headings for Content Structure. Content/Design Considerations Provide descriptive headings for sections of content for content structure.

Web accessibility depends on several components working together, including web technologies, web browsers and other “user agents”, authoring tools, and websites. The W3C Web Accessibility Initiative ( WAI) develops technical specifications, guidelines, techniques, and supporting resources that describe accessibility solutions.

When laying out a page, headings provide a semantic way to lay out sections of content. A heading element briefly describes the topic of the section it introduces. Heading elements are used by users of AT to navigate a page quickly and to understand the structure of a page.