What is the “perceivable” principle of web accessibility?
Making the output of web content available through multiple sensory modalities.
- Provide text alternatives for non-text content
- Provide captions and other alternatives for multimedia
- Create content that can be presented in different ways including assistive technologies without losing meaning
- Make it easier for users to see and hear content
What is the “operable” principle of web accessibility?
Making the input methods of web content functionally available to a wide range of input devices.
- Make all functionality available from a keyboard
- Give users enough time to read and use content
- Do not use content that causes seizures or physical reactions
- Help users navigate and find content
- Make it easier to use inputs other than a keyboard
What are some of the input devices to keep in mind when designing for operability?
- Mouse or touchpad
- Keyboard
- Touchscreen
- Voice recognition software
- Other specialized input devices (most of which emulate the keyboard or mouse)
What is the “understandable” principle of web accessibility?
Making content and interfaces that people can comprehend
- Make text readable and understandable
- Make content appear and operate in predictable ways
- Help users avoid and correct mistakes
What is the “robust” principle of web accessibility?
Ensuring compatibility with a broad range of user agents, including assistive technologies
- Maximize compatibility with current & future user tools
Why does perceivability matter?
If you can’t perceive web content, it may as well not exist.
If you can’t see it, all types of visual info are completely useless unless there’s a digital text alternative so screen readers can convert text to sound or braille.
If you can’t hear, audio content is completely unusable and multimedia content like videos are much less useful, unless a text alternative is provided like caption or transcript.
What is the only way for people who are both deaf and blind to access web content?
Tactile/touch output (usually a refreshable braille device)
Why is digital text the most universal format?
Because it can be converted into all other useful sensory formats (vision, sound, touch). People who are blind, deaf, and deafblind can perceive it.
How do you make dynamic content perceivable?
Use ARIA (Accessible Rich Internet Applications) when a tab is “expanded” or “collapsed” or announce new content as it’s inserted into the DOM (Document Object Model).
If new content is added to page (e.g. error or confirmation message), blind users need to hear this info.
What are two ways to ensure a user who’s blind is aware of the state of a tab or an error message?
- Use ARIA live regions
- Move the browser’s focus to those areas to force SRs to read them
What are some examples of how not everyone uses a computer in the same way?
- Someone with tremors in their hands might find it difficult to use a mouse or touchpad
- Some people have little or no movement in their limbs and may need device that senses movements in their cheek muscles or track eye gaze across screen or interpret speech as voice commands
What is meant by in, within, through, and out?
- You have be able to navigate into web components
- Use the features within them
- Navigate through them
- Navigate out of all of them
No matter what input device you’re using
How do you script for device independence?
Plain web content without any scripting or dynamic features is mostly device-independent by default.
Use device-independent event handlers (e.g. onfocus, onblur, onselect) rather than device-specific event handlers (e.g. onmouseover, onmouseout, onblclick), or provide mouse-specific event handler and redundant keyboard specific event handler – test both ways and on touch screens
What does it mean to “control the focus” and what are examples of how to do this?
- Pay attention to location of programmatic focus when creating dynamic interactions (usually the same as keyboard focus)
- When you create popup modal, ensure focus automatically lands on modal dialog
- When user exits popup modal, make sure focus goes back to previous focus location
- Don’t let the focus get lost
What are suggestions related to timing and operability?
- Ensure people have enough time to interact with content
- Session timeouts are allowed as long as you give user sufficient warning (e.g. in popup notification, and make sure popup is accessible)
Why are keyboards important to accessibility?
You can accomplish near-universal operability of web content by making it keyboard-accessible.
Everyone, incl. those without disabilities, use keyboards. Specialized input devices also emulate functionality of a keyboard
But still make sure to test of mouse accessibility (some devices like eye gaze tracking emulate mouse) – if you can use web content with a keyboard and mouse, chances are high you can use it on every other device
What are ways you can create understandable content?
- Specify the language
- Simplify the reading or vocabulary level
- Limit or avoid terminology or concepts that are unfamiliar or complex
- Provide supplemental formats
Why should you specify the language of text?
If language isn’t designated in markup, SR will read using pronunciation of whatever language is in user’s default settings. So if user speaks multiple languages, SR will not automatically switch between those languages & use wrong pronunciation.
Why should you simplify the reading or vocabulary level and what are some ways that reading can be challenging?
Why: reading disorders are common
Challenges:
- Long or unfamiliar words
- Long sentences
- Complex sentence construction
- Unclear wording
- Long passages of text (break up text into sections with headings, shorter paragraphs, lists)
- Lines of text that are too close to each other (usually best to include some blank visual space between lines of text)
Why is it important to limit terminology or concepts that are unfamiliar or complex?
Can be confusing:
- unfamiliar technical jargon
- slang
- culturally-specific words & concepts
Some people with more generalized cognitive disabilities are unable to understand complex ideas & abstractions
Why/how should you provide supplemental formats?
- Some people can’t read at all so simplifying text won’t help them
- Provide alternative formats (images, audio, video) and present that as directly and simply as possible
Do you have to create alternative formats?
If your main audience is people who can’t read, you should do that, but for general audiences you don’t. Not realistic for all cases, but providing supplemental formats can benefit people with various kinds of cognitive disabilities
What are some ways to prevent user errors when they interact with a web page?
- Provide instructions, hints, and contextual help, usually at beginning such as purpose of interaction and what user should do. Visually note any special constraints and communicate to SR users
- Provide feedback with confirmation and error messages. Tell user whether an interaction was successful or not. Ensure the messages are available to both sighted & SR users
How do you provide consistency or predictability to a website?
- Websites with multiple pages or views should maintain consistent look & feel across pages & views
- Visual layout and reading order/tab order shouldn’t change radically, main nav should generally contain same links, and text in those links should be consistent
- Form controls, custom controls, custom widgets should behave in standard ways, in line with common conventions
- Generally a bad idea to design completely new and different way of interacting with web components
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Theoretical Models of Disability21
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Categories and Characteristics of Disabilities70
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Disability Statistics13
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Disability Etiquette17
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Benefits of Accessible Design14
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Web Accessibility Principles25
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Universal Design for the Web13
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Universal Design for the Physical World87
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Universal Design for Learning21
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Usability and Accessibility6
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Accessibility Standards and Laws39
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Accessibility Across the Organization5
