This doc can help you to understand how the tests in Accessibility Checker align with Web Content Accessibility Guidelines (WCAG) levels of conformance.
For more information on what WCAG is or which level your organization should meet, please see these articles:
- WCAG 2.1 Explained
- WCAG 2.2 Explained & How to Test for It
- WCAG Conformance Levels Comparison: Which One You Should Follow
WCAG Version
All of the Accessibility Checker rules were created based on WCAG version 2.1. We do not yet have checks for WCAG 2.2; however, adding checks for WCAG 2.2 is on our roadmap.
If you want to conform only to WCAG 2.0, then you will need to reference the version of the relevant success criteria for each rule to determine if it is WCAG 2.0 or 2.1. We do not currently have a quick reference comparing WCAG 2.0 to 2.1. We strongly advise that you go beyond WCAG 2.0 with your website’s accessibility.
Which WCAG Success Criteria Are Relevant
If you want to know which WCAG success criteria are relevant to any given check, the best way to see that is in the documentation for the check. Each check includes a section that lists the relevant WCAG 2.1 success criteria.
An important thing to note is that while some checks only cover one success criterion, many of them apply to multiple criteria. For example, these are the relevant success criteria for the Empty Heading Tag error:
The presence of an empty heading tag could fail four different WCAG success criteria: two at level A, one AA, and one AAA. This is the case for many of our checks.
Accessibility Checker Checks by Conformance Level
The following lists show Accessibility Checker errors and warnings grouped by WCAG conformance levels. The checks are tagged based on the conformance levels of relevant success criteria. As noted above, some checks have multiple relevant success criteria; if the relevant criteria fall under multiple conformance levels, that check will be listed in more than one list below.
Note: If you are striving for AA conformance, you will need to pass checks listed in both the AA and A lists.
WCAG Level A
Errors
- Ambiguous Anchor Text
- Blinking or Scrolling Content
- Broken ARIA Reference
- Broken Skip or Anchor Link
- Duplicate Form Label
- Empty Button
- Empty Heading Tag
- Empty Link
- Empty or Missing Form Label
- Empty or Missing Table Header
- iFrame Missing Title
- Image Map Missing Alternative Text
- Image Missing Alternative Text
- Improper Use of Link
- Incorrect Heading Order
- Linked Image Missing or Empty Alternative Text
- Long Description Invalid
- Missing Language Declaration
- Missing Title
- Missing Transcript
Warnings
- A Slider is Present
- A Video is Present
- ARIA Hidden
- Duplicate Alternative Text
- Image Animated GIF
- Image Empty Alternative Text
- Image Long Alternative Text
- Link Opens New Window or Tab
- Link to MS Office File
- Link to Non-HTML File
- Link to PDF
- Low-quality Alternative Text
- Missing Subheadings
- Possible Heading
- Tab Order Modified
WCAG Level AA
Errors
- Duplicate Form Label
- Empty Heading Tag
- Empty or Missing Form Label
- Improper Use of Link
- Incorrect Heading Order
- Insufficient Color Contrast
- Missing Language Declaration
- Missing Transcript
- Zooming and Scaling Disabled
Warnings
- A Video is Present
- Image Animated GIF
- Link to MS Office File
- Link to Non-HTML File
- Link to PDF
- Missing Subheadings
- Possible Heading
WCAG Level AAA
Errors
- Blinking or Scrolling Content
- Empty Heading Tag
- Image Map Missing Alternative Text
- Incorrect Heading Order
- Insufficient Color Contrast
- Missing Transcript
- Readability & Simplified Summary
