Web Accessibility Principles Flashcards
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)
