Accessibility Guide for WCAG 2.2 (A)

Elements with scrollable content must be keyboard-accessible.

This rule searches scrollable content for elements that can be focused to enable keyboard navigation. When the focus shifts to an element within a scrollable region, keyboard navigation shouldn’t stop working.

What this Accessibility Rule Checks

Check to see if the scrollable area has keyboard access.

A label element with a programmatic association must be included for each select element.

To make forms accessible, they must have clear form labels. Even if a form element isn’t programmatically named, sighted users can usually tell what it’s for when they see checkboxes, radio buttons, input fields, etc. To identify form fields, screen reader users need clear form labels. All form elements should have labels to remove confusion and make the product more accessible.

Screen reader users are in the dark about the expected input data when form elements lack labels. Without a defined label connection (or redundant text acting as a label), screen readers cannot automatically determine information about input items.

What this Accessibility Rule Checks

ensures that each select element has a label that is associated with it programmatically.

An image map that is server-side rather than client-side is present in the page.

Server-side image maps can’t be used with a keyboard since mouse clicks are needed to access the links they contain, rendering them unavailable to users who only use keyboards.

The server-side software used to process the image map receives the locations of the mouse click from server side image maps. They are not keyboard accessible since they rely on mouse clicks, although client-side image mappings are. Additionally, unlike the regions of a client-side picture map, actionable areas of a server-side image map cannot be provided with text alternatives.

What this Accessibility Rule Checks

Makes sure that server-side image maps are not used.

All summary elements used as a control for a details element must have a discernible, accessible name.

Screen reader users are unable to discern the purpose of summary elements that lack an accessible name. This prevents them from understanding the purpose of the control and will likely mean they won’t find information hidden with the details element.

The most reliable method for creating an accessible summary element is to put a text inside the summary element, like in this example:

<details>
  <summary id="text">Title</summary>
  ...
</details>

As an alternative, you can also give a summary element a hidden alternative text. This is ideal for situations where the summary has no visible text, such as when using a CSS background image. There are a few ways to provide a hidden alternative, including:

• Using the aria-label="text alternative here" attribute.
• Using the aria-labelledby="id-to-element-with-text" attribute.
• Using the title="tooltip alternative here" attribute.

What this Accessibility Rule Checks

This rule ensures that all summary elements used as a control for a details element have a discernible and accessible name.

Ensures that SVG elements with the roles img, graphics-document or graphics-symbol have a text alternative that is accessible.

In order to make information provided by non-text material (including SVG graphics) accessible, Success Criterion 1.1.1 requires the usage of a text alternative. Because they can be portrayed through any sensory modality (for example, visual, auditory, or tactile) to suit the user’s needs, text alternatives are a fundamental method of making information accessible. By including text alternatives, a wider range of user agents can present the content in different ways.

For instance, a person who is blind can request that the text equivalent of an image be read out using synthetic speech. An audio file’s text alternative can be presented for people who cannot hear it, allowing them to read it. Text alternatives will eventually make it simpler to translate information into sign language or a more basic version of the same language.

What this Accessibility Rule Checks

The algorithm for this rule returns:

• True if the element has a <title>code child

<svg id="target"><title>Time II: Party</title></svg>

• True if the <title> child has text nested in another element.

<svg id="target"><title><g>Time II: Party</g></title></svg>

• False if the element has no <title> child.

<svg id="target"></svg>

• False if the <title> child is empty.

<svg id="target"><title></title></svg>

• False if the <title> is a grandchild.

<svg id="target"><circle><title>Time II: Party</title></circle></svg>

• False if the <title> child has only whitespace.

<svg id="target"><title> \t\r\n </title></svg>

• False if there are multiple titles and the first is empty.

<svg id="target"><title></title><title>Time II: Party</title></svg>

The headers attribute is one of the primary ways to programmatically associate data cells with their corresponding header cells in HTML tables. It works by referencing the id values of th elements. When these references point to elements outside the table — or to id values that don’t exist at all — the association breaks, and assistive technology can no longer convey the relationship between data and headers.

This primarily affects users who are blind or deafblind and rely on screen readers. When navigating a data table, screen readers announce the relevant column and row headers as users move from cell to cell. This “table navigation mode” is essential for understanding the data in context. If the headers attribute references are broken, users may hear no header announcements or incorrect ones, making it impossible to interpret the data.

This rule relates to WCAG 2.0, 2.1, and 2.2 Success Criterion 1.3.1: Info and Relationships (Level A), which requires that information, structure, and relationships conveyed visually are also available programmatically. It also applies to Section 508 requirements that row and column headers be identified for data tables and that markup be used to associate data cells with header cells in tables with two or more logical levels of headers.

How to Fix the Problem

There are three common approaches to associating headers with data cells:

Use the scope attribute (simplest approach)

For straightforward tables, adding scope="col" to column headers and scope="row" to row headers is the easiest and most reliable method. No id or headers attributes are needed.

Use id and headers attributes (for complex tables)

For tables with multiple levels of headers or irregular structures, you can assign an id to each th element and then list the relevant id values in each td‘s headers attribute. The critical rule is: every id referenced in a headers attribute must belong to a th in the same <table> element.

Use scope="colgroup" and scope="rowgroup"

For tables with headers that span multiple columns or rows, the colgroup and rowgroup values of scope can indicate which group of columns or rows a header applies to.

Examples

Incorrect: headers attribute references an id outside the table

In this example, the headers attribute on data cells references id="name", which exists on an element outside the table. This will trigger the rule violation.

<h2 id="name">Name</h2>
<table>
  <tr>
    <th id="time">Time</th>
  </tr>
  <tr>
    <td headers="name time">Mary - 8:32</td>
  </tr>
</table>

Incorrect: headers attribute references a non-existent id

Here, headers="runner" refers to an id that doesn’t exist anywhere in the table.

<table>
  <tr>
    <th id="name">Name</th>
    <th id="time">1 Mile</th>
  </tr>
  <tr>
    <td headers="runner">Mary</td>
    <td headers="runner time">8:32</td>
  </tr>
</table>

Correct: Using scope for a simple table

For simple tables, scope is the preferred method and avoids the pitfalls of headers entirely.

<table>
  <caption>Greensprings Running Club Personal Bests</caption>
  <thead>
    <tr>
      <th scope="col">Name</th>
      <th scope="col">1 Mile</th>
      <th scope="col">5 km</th>
      <th scope="col">10 km</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <th scope="row">Mary</th>
      <td>8:32</td>
      <td>28:04</td>
      <td>1:01:16</td>
    </tr>
    <tr>
      <th scope="row">Betsy</th>
      <td>7:43</td>
      <td>26:47</td>
      <td>55:38</td>
    </tr>
  </tbody>
</table>

Correct: Using id and headers for a complex table

When a table has multiple levels of headers, the headers attribute allows you to explicitly associate each data cell with the correct set of headers. All referenced id values are on th elements within the same table.

<table>
  <caption>Items Sold August 2016</caption>
  <thead>
    <tr>
      <td colspan="2"></td>
      <th id="clothes" scope="colgroup" colspan="3">Clothes</th>
      <th id="accessories" scope="colgroup" colspan="2">Accessories</th>
    </tr>
    <tr>
      <td colspan="2"></td>
      <th id="trousers" scope="col">Trousers</th>
      <th id="skirts" scope="col">Skirts</th>
      <th id="dresses" scope="col">Dresses</th>
      <th id="bracelets" scope="col">Bracelets</th>
      <th id="rings" scope="col">Rings</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <th id="belgium" scope="rowgroup" rowspan="3">Belgium</th>
      <th id="antwerp" scope="row">Antwerp</th>
      <td headers="belgium antwerp clothes trousers">56</td>
      <td headers="belgium antwerp clothes skirts">22</td>
      <td headers="belgium antwerp clothes dresses">43</td>
      <td headers="belgium antwerp accessories bracelets">72</td>
      <td headers="belgium antwerp accessories rings">23</td>
    </tr>
    <tr>
      <th id="gent" scope="row">Gent</th>
      <td headers="belgium gent clothes trousers">46</td>
      <td headers="belgium gent clothes skirts">18</td>
      <td headers="belgium gent clothes dresses">50</td>
      <td headers="belgium gent accessories bracelets">61</td>
      <td headers="belgium gent accessories rings">15</td>
    </tr>
    <tr>
      <th id="brussels" scope="row">Brussels</th>
      <td headers="belgium brussels clothes trousers">51</td>
      <td headers="belgium brussels clothes skirts">27</td>
      <td headers="belgium brussels clothes dresses">38</td>
      <td headers="belgium brussels accessories bracelets">69</td>
      <td headers="belgium brussels accessories rings">28</td>
    </tr>
  </tbody>
</table>

In this complex example, each data cell’s headers attribute lists the id values of every relevant header — the country group, the city, the product category, and the specific product. Every referenced id belongs to a th within the same <table>, so the associations are valid and screen readers can announce the full context for each cell.

Tips for avoiding this issue

• Double-check id values. A common cause of this violation is a typo in either the id on the th or in the headers attribute value on the td.
• Don’t reuse id values across tables. If you copy markup from one table to another, ensure id values are unique within the page and that headers attributes reference the correct table’s th elements.
• Prefer scope when possible. For simple tables with a single row of column headers and/or a single column of row headers, scope is simpler and less error-prone than id/headers.
• Use id and headers for genuinely complex tables — those with multiple header levels, merged cells, or irregular structures where scope alone cannot convey all relationships.

Markup for data tables can be tedious and perplexing. Tables should be marked up correctly in terms of header format and semantics. Table navigation is made easier by features in screen readers, but for these capabilities to function properly, the tables must be precisely marked up.

Tables are announced in a certain way by screen readers. The potential for unclear or erroneous screen reader output exists when tables are not properly marked up.

Screen reader users are unable to correctly understand the relationships between the cells and their contents visually when tables are not adequately structured and marked up semantically.

What this Accessibility Rule Checks

Verifies that each header cell is referred to as a header of a column or row in data tables by checking their markup.

A track element with the property set to kind="captions" is required for an HTML5 video element. For deaf viewers, the captions must include all audible cues from the video, such as dialogue, musical cues, sound effects, and other pertinent information.

Users who are hard of hearing have limited or no access to a video’s content if it lacks a caption. Even if there is a captioning track, make sure it includes all of the video’s important content and not just the dialogue.

Without captions, deaf viewers are able to see everything in the video but are unable to hear anything. The dialogue, narration, and other crucial sounds that are not spoken by people—such as “dramatic instrumental music,” clapping, screaming, or other sounds that create the scene, provide context, or otherwise give meaning to the video—are not audible to deaf viewers without a caption track.

What this Accessibility Rule Checks

Makes sure all video elements have captions.