HTML Guide

According to the ARIA specification, the attribute aria-rowspan is expected to have a positive integer value. A positive integer is a whole number greater than zero.

Explanation

• aria-rowspan: This attribute is used in ARIA-enabled tables to indicate how many rows a cell should span within its row group. It is often used in elements like gridcell or rowheader within roles that imply grid-like structures, such as grid or treegrid.

Example of Incorrect Usage

<div role="gridcell" aria-rowspan="0">Content</div>

In this example, aria-rowspan is set to "0", which is not a valid positive integer.

Correct Usage

To resolve the issue, you should specify a positive integer. For example, if the cell should span one row, you can write:

<div role="gridcell" aria-rowspan="1">Content</div>

If the cell should span multiple rows, adjust the number accordingly:

<div role="gridcell" aria-rowspan="2">Content</div>

Considerations

• Make sure the role attribute is correctly associated with an element that can logically have a row and grid structure, such as gridcell.
• Ensure that the aria-rowspan value aligns with the structure of your grid or table, representing the actual number of rows that the element is spanning.

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.

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.

The rel attribute defines the relationship between a linked resource and the current document. Valid on <link>, <a>, <area>, and <form>, the supported values depend on the element on which the attribute is found.

Here’s an example of using the rel attribute to link a document to a CSS stylesheet:

<link rel="stylesheet" href="default.css" />

Here’s an example os using the rel attribute to tell search engine spiders to ignore the link relationship with another document:

<a href="https://example.com" rel="nofollow">more info</a>

The <dl> element, used to create a definition lists that matches some terms with their definitions, has nesting issues related to <div> elements used with it.

Using aria-required on a div element requires more context about that element, by providing one of the attributes aria-expanded, aria-valuemax, aria-valuemin, aria-valuenow, role.

When possible, you should prefer semantic tags like input, select and textarea, and use the required attribute, but when form controls are created using non-semantic elements, such as a div element, the aria-required attribute should be included with a value of true to indicate to assistive technologies that user input is required on the element for the form to be submittable. In that case, other attributes might be needed to make the element valid.

For example, we could build a radiogroup using a div like this:

<div aria-required="true">
  <div data-value="One"></div> 1
  <div data-value="Two"></div> 2
  <div data-value="Three"></div> 3
</div>

This HTML snippet would then be decorated using CSS and added functionality using JavaScript. However, the W3C validator will complain that the element div is missing one of the attributes aria-expanded, aria-valuemax, aria-valuemin, aria-valuenow, role.

We can fix that by adding the appropiate role to that div element, like this:

<div aria-required="true" role="radiogroup">
  <div data-value="One"></div> 1
  <div data-value="Two"></div> 2
  <div data-value="Three"></div> 3
</div>

Here is an example showing how to add the “role” attribute to the “div” element:

<div role="region">
    <!-- Your content goes here -->
</div>

In this example, the role attribute is added with the value radiogroup. You can choose the appropriate ARIA role based on the purpose or role of your div element.

Remember to also provide the necessary values for the specified attributes if you are adding aria-valuemax, aria-valuemin, or aria-valuenow to ensure proper accessibility and usability of your content.

The element X is not allowed as a child element of Y. For example, a <ul> element cannot have a <div> child element.

An </a> end tag has been found to violate nesting rules. <a> tags can’t include other <a> tags inside. Most probable cause is an unclosed <a> tag, like in this example:

<a href="one.html">Page 1
<a href="two.html">Page 2</a>

An end tag </b> has been found in an incorrect place within the document, violating nesting rules. A common case is closing it before closing other nested tags, for example:

<!-- This line is incorrect as the <b> tag was closed before the nested <a> tag -->
<b><a href="#">link</b></a>

<!-- This line is OK as every end tag respects the nesting rules -->
<b><a href="#">link</a></b>