The “list” role is unnecessary for element “ul”.

The alert role can be used to tell the user an element has been dynamically updated. Screen readers will instantly start reading out the updated content when the role is added. The element <ul> doesn’t accept this kind of role, consider using other element like <p> or <div>.

The alert role is used to communicate an important and usually time-sensitive message to the user. When this role is added to an element, the browser will send out an accessible alert event to assistive technology products which can then notify the user about it. The alert role is most useful for information that requires the user’s immediate attention.

Use a valid landmark or list role: remove role="list" from the section, or replace the element with a proper list (ul/ol) or a container that supports role="list".

The role attribute must use values allowed by ARIA for the given context. A section element is a landmark and must not be given role="list". If you intend to mark up a list of items, use semantic list elements: ul/ol with li. If you truly need ARIA list semantics (e.g., for custom components), use a neutral container (div) with role="list" and child elements with role="listitem". Prefer native HTML lists over ARIA roles because they provide built-in semantics and better accessibility. Examples:

• Native list: use ul + li.
• ARIA list (only if native markup isn’t possible): div role="list" containing div role="listitem".

HTML Examples

Example showing the validation error

<section role="list">
  <div>Item A</div>
  <div>Item B</div>
</section>

Fixed using native list semantics (recommended)

<ul>
  <li>Item A</li>
  <li>Item B</li>
</ul>

Fixed using ARIA roles on neutral elements (when custom UI prevents native lists)

<div role="list">
  <div role="listitem">Item A</div>
  <div role="listitem">Item B</div>
</div>

The role attribute value navigation is invalid for a ul element, as it should be used with a nav element or similar suitable elements.

In HTML, the role attribute defines what an element represents in the context of accessible web technologies, primarily for assistive tools like screen readers. The nav element represents a section of a page intended for navigational links, and it inherently provides the role of navigation. If you want to make a ul element serve as navigation, it is more appropriate to use it inside a nav element, or alternatively, set a valid ARIA role on the element itself.

Detailed Explanation

HTML5 introduced a specific set of elements with implicit ARIA roles and behaviors, like the nav element, which implicitly has the navigation role. For backward compatibility or advanced use cases, developers might explicitly set ARIA roles using the role attribute. However, setting an invalid role can lead to accessibility issues, as seen with trying to assign navigation to a ul element.

Instead of applying the navigation role to a ul directly, wrap your ul with a nav element.

The allowed ARIA roles for an ul element are directory, group, listbox, menu, menubar, none, presentation, radiogroup, tablist, toolbar and tree, but not navigation.

Examples

Here is how you can use the nav element with a ul.

<nav>
  <ul>
    <li><a href="#home">Home</a></li>
    <li><a href="#about">About</a></li>
    <li><a href="#contact">Contact</a></li>
  </ul>
</nav>

The role attribute in HTML is used to define the accessibility role of an element, which helps assistive technologies understand the purpose or type of the element. The value tabpanel is not appropriate for a <ul> element, which is used for unordered lists.

The role of tabpanel is intended to be used with elements that represent a tab panel, which is part of a tabbed interface. A tabbed interface consists of elements with roles like tablist, tab, and tabpanel. Typically, tabpanel is used with containers that house the content associated with a tab, such as a <div>.

To fix this error, ensure that the tabpanel role is applied to the correct element. Here’s a simple example of how a tab interface can be structured correctly:

<div role="tablist" aria-label="Sample Tabs">
  <button role="tab" aria-controls="panel-1" id="tab-1">Tab 1</button>
  <button role="tab" aria-controls="panel-2" id="tab-2">Tab 2</button>
</div>

<div role="tabpanel" id="panel-1" aria-labelledby="tab-1" hidden>
  <p>Content for Tab 1.</p>
</div>

<div role="tabpanel" id="panel-2" aria-labelledby="tab-2" hidden>
  <p>Content for Tab 2.</p>
</div>

In this example:

• The role tablist is applied to the container element that directly contains the tab elements.
• Each button serving as a tab has the role of tab.
• Each tab panel, which contains the content for a tab, has the role of tabpanel.

Avoid using tabpanel on non-semantic or incorrectly associated elements like <ul>. Instead, use elements like <div> or <section> for tab panels, ensuring the roles align with the intended roles in a tabbed interface.

There can only be one visible <main> element in a document. If more are needed (for example for switching between them with JavaScript), only one can be visible, the others should be hidden toggling the hidden attribute.

Example of 2 main elements, where only one is visible:

<main>
  <h1>Active main element</h1>
<!-- content -->

</main>

<main hidden>
  <h1>Hidden main element</h1>
<!-- content -->

</main>

The HTML <figure> element is used to encapsulate media content, such as an image or graphic, along with a descriptive <figcaption>. When a <figcaption> is present within a <figure>, it inherently provides the semantics of the <figure>, making it self-explanatory without needing an additional role attribute.

Explanation

• <figure> element: Represents self-contained content, potentially with an optional caption specified by a <figcaption> element. This is inherently recognized for its semantics as a figure with a caption.

• <figcaption> element: Provides a caption or description for the content of the <figure>. This helps in describing the media or content included in the <figure> element.

• role attribute: This attribute is used to define an explicit accessibility role for an element. However, in cases where the element’s native semantics are explicit and sufficient, such as a <figure> with a <figcaption>, adding a role attribute might override or conflict with the inherent meaning.

Solution

Remove the role attribute from the <figure> element when it contains a <figcaption>.

Example of Incorrect Code:

<figure role="figure">
  <img src="cat.jpg" alt="A cute cat">
  <figcaption>A cute cat looking at the camera.</figcaption>
</figure>

Corrected Code:

<figure>
  <img src="cat.jpg" alt="A cute cat">
  <figcaption>A cute cat looking at the camera.</figcaption>
</figure>

In the corrected example, the <figure> element does not have a role attribute, allowing it to maintain its inherent semantic value.

A role="cell" element must be a child of an element with role="row" for correct ARIA relationships.

According to the ARIA specification, role="cell" should be directly contained within a parent with role="row", which itself should usually be inside an element with role="rowgroup" or role="table". This structure allows assistive technologies to interpret your table semantics correctly.

Correct Structure Example:

<div role="table">
  <div role="row">
    <div role="cell">Row 1, Cell 1</div>
    <div role="cell">Row 1, Cell 2</div>
  </div>
  <div role="row">
    <div role="cell">Row 2, Cell 1</div>
    <div role="cell">Row 2, Cell 2</div>
  </div>
</div>

Incorrect Structure Example (missing row):

<div role="table">
  <div role="cell">Cell without row</div>
</div>

How to fix:
Wrap any element with role="cell" inside an element with role="row". This ensures both validity and proper accessibility support.

A role="columnheader" element must be a child of or associated with a role="row" element.

In HTML, ARIA roles such as columnheader are used to improve accessibility for assistive technologies. According to the ARIA specification, a columnheader role should appear inside an element with role="row", which itself should be inside an element with role="table" or role="grid". This structure mimics how native tables are constructed with <th> elements inside <tr>s.

Correct structure:

• role="table" or role="grid" contains one or more elements with role="row".
• Each role="row" contains one or more elements with role="columnheader" (or role="cell").

Example using ARIA roles for a simple table:

<div role="table" aria-label="Sample Table">
  <div role="row">
    <div role="columnheader">Name</div>
    <div role="columnheader">Age</div>
  </div>
  <div role="row">
    <div role="cell">Alice</div>
    <div role="cell">30</div>
  </div>
</div>

Best practice:
Whenever possible, use native table elements, which have built-in roles and accessibility, reducing the chance of ARIA misuse.

Example using native table markup:

<table>
  <tr>
    <th>Name</th>
    <th>Age</th>
  </tr>
  <tr>
    <td>Alice</td>
    <td>30</td>
  </tr>
</table>

Ensure that any element with role="columnheader" is always contained within a parent with role="row". Avoid placing role="columnheader" directly inside a container without the appropriate role="row" ancestor.

To fix this issue, ensure that an element with role="listitem" is contained within an element with role="list" or role="group". Here’s how you can structure your HTML correctly:

Incorrect Example

<div role="listitem">Item 1</div>
<div role="listitem">Item 2</div>

Correct Example

<div role="list">
  <div role="listitem">Item 1</div>
  <div role="listitem">Item 2</div>
</div>

Alternatively, you can use role="group" if it’s a nested list.

Correct Example with Nested List

<div role="list">
  <div role="listitem">Item 1</div>
  <div role="group">
    <div role="listitem">Item 1.1</div>
    <div role="listitem">Item 1.2</div>
  </div>
  <div role="listitem">Item 2</div>
</div>

This ensures that the role="listitem" elements are correctly contained.

To fix the W3C HTML Validator issue stating that an element with a role="menuitem" must be contained in, or owned by, an element with role="menubar" or role="menu", you need to ensure that your menuitem elements are properly nested within a menubar or menu element. This is important for accessibility, as it helps assistive technologies understand the structure and relationship of the elements.

The menuitem role indicates the element is an option in a set of choices contained by a menu or menubar.

Here is a step-by-step guide to fixing this issue:

1. Using role="menubar"

If your menuitem elements are part of a horizontal menu (like a navigation bar), they should be nested within an element with role="menubar".

Example:

<nav role="menubar">
  <div role="menuitem">Home</div>
  <div role="menuitem">About</div>
  <div role="menuitem">Contact</div>
</nav>

2. Using role="menu"

If your menuitem elements are part of a submenu or a vertical menu, they should be contained within an element with role="menu".

Example:

<div role="menu">
  <div role="menuitem">Item 1</div>
  <div role="menuitem">Item 2</div>
  <div role="menuitem">Item 3</div>
</div>

Ensuring Proper Nesting

Ensure that all your menuitem elements are either directly or indirectly (via a child-parent relationship) contained within a menubar or menu element.

Complete Example with Nested Menus:

Here is a more complex example, including nested menus for a drop-down scenario.

Example:

<nav role="menubar">
  <div role="menuitem">Home</div>
  <div role="menuitem">
    About
    <div role="menu">
      <div role="menuitem">Team</div>
      <div role="menuitem">History</div>
    </div>
  </div>
  <div role="menuitem">Contact</div>
</nav>

In this example, the main navigation (menubar) contains menuitem elements, and one of those menuitem elements contains a nested menu with additional menuitem elements inside it.

By ensuring your menuitem elements are contained within appropriate parent elements (menubar or menu), you will resolve the W3C HTML Validator issue and improve your web page’s accessibility.