網站無障礙介紹

by Makzan.

for CPTTM, 2022-11-26

https://slides.com/makzan/web-accessibility-workshop-2021-689c9c

Slides URL

https://slides.com/makzan/web-accessibility-workshop-2021-689c9c

Thomas Mak

• 1999 Start web design with (Macromedia) Flash 4.
• 2000 Designing website with table based layout & Adobe Flash.
• 2008 Designing website with HTML+CSS layout.
• 2010 My first book got published.
• Now, WorldSkills Web Technologies Competition Manager.

There is a guideline, right?

Let’s follow it

There is a guideline, right?

Let’s follow it

There is a guideline, right?

1. Learn how every one use the web.
2. Learn the guideline.

How we use web?

How disabilities use web?

How elders use web?

Photo from wikipedia https://en.wikipedia.org/wiki/Tim_Berners-Lee

https://www.w3.org/WAI/

4 Principles

Perceivable

Operable

Understandable

Robust

1. Perceivable
2. Operable
3. Understandable
4. Robust

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

https://www.w3.org/WAI/perspective-videos/

User Agent Accessibility Guidelines (UAAG)

Web Content Accessibility Guidelines (WCAG)

Authoring Tool Accessibility Guidelines (ATAG)

WCAG 2.1

Web Content Accessibility Guidelines

https://www.w3.org/WAI/standards-guidelines/wcag/

Case Study: 市政署網站

https://m.iam.gov.mo/c/news/detail/270e9c8c-4f19-46a9-9dc6-68bb540308c6

Case Study: 身份證明局網站

http://www.dsi.gov.mo

WAVE

https://wave.webaim.org

Voice Over

Enable Voice Over

iOS
https://www.apple.com/accessibility/iphone/vision/

Android
https://support.google.com/accessibility/android/answer/6007100?hl=en

Press both volume keys

Press both volume keys for 3 seconds.

If TalkBack doesn't turn on right away, press both volume keys again for 3 seconds.

Enable Voice Over

macOS
https://support.apple.com/en-mo/guide/voiceover/welcome/mac

Windows: NVDA

https://www.nvaccess.org/download/

Tool: NVDA

Non-Vision Desktop Access

https://www.nvaccess.org/download/

NVDA Recommended add-ons

Focus Highlight

by Takuya Nishimoto

https://addons.nvda-project.org/addons/focusHighlight.en.html​

Voice Over Demo

Headings structure

Headings

• SC 2.4.6 Headings and Labels (AA)
• SC 2.4.10 Section Headings (AAA)

When h1 is missing

When h1 is missing

Reader 1

Reader 2

{h/}

HeadingsMap

https://addons.mozilla.org/en-US/firefox/addon/headingsmap/

Importance of Title

Success Criterion 2.4.2 Page Titled (A)

Where are titles used?

Links and Copywriting

Purpose of Links

SC 2.4.4 Link purpose in context (A) 

SC 2.4.9 Link purpose (link text only) (AAA)

2.4.4 (A)

The purpose of each link can be determined from the link text alone or from the link text together with its programmatically determined link context, except where the purpose of the link would be ambiguous to users in general.

2.4.9 (AAA)

A mechanism is available to allow the purpose of each link to be identified from link text alone, except where the purpose of the link would be ambiguous to users in general.

Link Purpose (Link Only)

Link Purpose (In Context)

Example

Example

Observation Exercise

In your daily web browsing, do you often see links without enough description?

Alternative Text

• How to write alt
• When alt is empty
• When alt is missing

☹️ Example

Note on CAPTCHA

Note on CAPTCHA

Requiring two different forms of CAPTCHA on a given site ensures that most people with disabilities will find a form they can use.

but...

https://www.w3.org/WAI/WCAG21/Understanding/non-text-content

Note on CAPTCHA

Requiring two different forms of CAPTCHA on a given site ensures that most people with disabilities will find a form they can use.

but...

https://www.w3.org/WAI/WCAG21/Understanding/non-text-content

Organizations motivated to conform to WCAG should be aware of the importance of this topic and should go as far beyond the minimum requirements of the guidelines as possible.

Note on CAPTCHA

• Providing more than two modalities of CAPTCHAs
• Providing access to a human customer service representative who can bypass CAPTCHA
• Not requiring CAPTCHAs for authorized users

https://www.w3.org/WAI/WCAG21/Understanding/non-text-content

Labeling for Inputs

Example: gov.uk

https://www.gov.uk/personal-tax-account/sign-in/prove-identity

aria-label

aria-labelledby

aria-describedby

☹️ Example

https://account.gov.mo/zh-hant/activate/​

Provide transcript

• Time-based alternative text

Example: TED

https://www.ted.com/talks/tyler_dewitt_hey_science_teachers_make_it_fun/transcript

Some Free transcription tools

• Youtube Studio
• Amara
  https://amara.org/
• Web Captioner (for Live)
  https://webcaptioner.com

Benefits of Transcripts

• People who are deaf or hard of hearing.
• People who won't spend the time to listen to the audio or watch the video, but will skim a transcript.
• People who have difficulty processing auditory information, for example, because of cognitive disability.
• People who are not proficient in the language who find it easier to read than listen.
• People with low bandwidth connections who don't want to download the larger audio or video file.
• People who pay for bandwidth usage and thus don't want to download the larger audio or video file. This is often an issue with phones and other mobile devices.
• People who cannot play the audio because they are in a noisy environment and they can't hear it.
• People who cannot play the audio because they are in a quiet environment and they don't want to disturb others.

http://www.uiaccess.com/transcripts/transcripts_on_the_web.html​

Benefits of Transcripts

• People who are deaf or hard of hearing.
• People who won't spend the time to listen to the audio or watch the video, but will skim a transcript.
• People who have difficulty processing auditory information, for example, because of cognitive disability.
• People who are not proficient in the language who find it easier to read than listen.
• People with low bandwidth connections who don't want to download the larger audio or video file.
• People who pay for bandwidth usage and thus don't want to download the larger audio or video file. This is often an issue with phones and other mobile devices.
• People who cannot play the audio because they are in a noisy environment and they can't hear it.
• People who cannot play the audio because they are in a quiet environment and they don't want to disturb others.

http://www.uiaccess.com/transcripts/transcripts_on_the_web.html​

Color Blindness

https://www.color-blindness.com/types-of-color-blindness/

https://codepen.io/makzan/debug/PoNvbGV

More CSS

Accessible Font Size

https://css-tricks.com/accessible-font-sizing-explained/

Variable unit

• use em, rem, %
• avoid setting root/body font-size

Responsive Font Size

by using clamp

Dynamic Type

for iOS

https://codepen.io/makzan/pen/4126fb2f58998375b8935d88eeee2290

Test in your device

Writing Accessibility Report

https://www.w3.org/WAI/eval/report-tool/

However, in the majority of situations using this methodology alone, without additional quality assurance measures, does not directly result in WCAG 2.0 conformance claims.

Exercise Time

Try to generate a report

by using WCAG-EM reporting  tool

https://www.w3.org/WAI/eval/report-tool/

Take away

Photo from wikipedia https://en.wikipedia.org/wiki/Tim_Berners-Lee

https://www.w3.org/WAI/