Accessibility Part 1
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What is accessibility and why should we care about it?
AEveryone has different preferences for how they live their life and accessibility is about accommodating everyone.
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Introducing WCAG
Web Content Accessibility Guidelines are a universal standard that codifies a series of testable, measurable statements called “success criteria”.
These guidelines apply to all web technologies (including mobile apps) and are the basis for global legal standards.
This course will only cover WCAG 2.0 but it has been updated and expanded upon to a more advanced set in WCAG 2.1.
https://www.w3.org/TR/WCAG20/
Level A Level AA Level AAA
Criterions that are likely to be a blocker for certain user groups
Standard that most companies aim to achieve
This is typically used for sites that are specifically targeting people with disabilities
Principles of WCAG
Perceivable Operable
Understandable Robust
1. Perceivable
Components must be presentable to users in ways they can perceive.
Non-text Content
All non-text content that is presented to the user should have a text alternative that serves the equivalent purpose.
Text alternatives are a primary way for making information accessible because they can be rendered through any sensory modality (for example, visual, auditory or tactile) to match the needs of the user. Providing text alternatives allows the information to be rendered in a variety of ways by a variety of user agents.
This includes images, icons, video, audio, and charts.
This image is not perceivable without seeing the image. This creates an adverse user experience for screen reader users and low- bandwidth users. An alternative text should be provided to improve this.
1) Describe the image
2) Adapt it to the context 3) Mark decorative images
What would be a more appropriate alt text?
As an exercise, have a think about a simple line chart. Think about what meaningful information would be relevant to the user you’d want to communicate.
Hint: it would be very hard to understand a list of coordinates.
Distinguishable
Text on the webpage must be legible. Text should be used instead images of text. The page must also not resist being zoomed in up to 200% and must not result in a loss of content or functionality.
The most common problem here is that the colour contrast of the text and the background (including images) must be sufficiently high.
In practice, this means:
4.5:1 contrast ratio for text smaller than 18pt 3:1 contrast ratio for text 18pt or larger
https://webaim.org/resources/contrastchecker/
Distinguishable
See you next time!
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