Non-text content
Web Accessibility Lesson 3
3.1 Alt and title for images
3.2 Notes on CAPTCHA
3.3 Examples of image links
3.4 Labeling for inputs
3.3 Video playback and download
3.4 Video caption
Tool: NVDA
Non-Vision Desktop Access
NVDA Recommended add-ons
Focus Highlight
by Takuya Nishimoto
Alternative Text
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...
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...
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
Labeling for Inputs
Labeling for Inputs
- label
- Cursor: pointer
Example: gov.uk
aria-label
aria-labelledby
aria-describedby
☹️ Example
Exercise: Let’s fix it
Three Flashes
Three Flashes
- No three or more flashes in any one second period.
- Especiall red flashes.
Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion.
Audio & Video playback
Pre-Recorded
Provide Audio version for Videos
- The audio should describe the important content of the video.
- Be ware that this audio description may not exactly be the audio extractino of the video.
Provide transcript
- Time-based alternative text
Example: TED
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.
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.
Live Captioning
