HTML Guide
The boolean required attribute, if present, indicates that the user must specify a value for the input before the owning form can be submitted.
If this property is not present, the input will be considered as optional. To mark an input as required, it’s enough to include the property without any value, or pass it the required value as in these examples:
Example:
<input type="text" required>
<input type="text" required="required">Learn more:
Related W3C validator issues
The only accepted value for the aria-required property is true.
The aria-required attribute indicates that user input is required on the element before a form may be submitted.
When a semantic HTML <input>, <select>, or <textarea> must have a value, it should have the required attribute applied to it. When form controls are created using non-semantic elements, such as a <div> with a role of checkbox, 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.
Example:
<div id="email_label">Email Address *</div>
<div
role="textbox"
contenteditable
aria-labelledby="email_label"
aria-required="true"
id="email"></div>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>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.
Elements with the role tab must either be a child of an element with the tablist role, or have their id part of the aria-owns property of a tablist.
An element with the tab role controls the visibility of an associated element with the tabpanel role. The common user experience pattern is a group of visual tabs above, or to the side of, a content area, and selecting a different tab changes the content and makes the selected tab more prominent than the other tabs.
Example:
<div class="tabs">
<div role="tablist" aria-label="Sample Tabs">
<button role="tab" aria-selected="true" aria-controls="panel-1" id="tab-1" tabindex="0">
First Tab
</button>
<button role="tab" aria-selected="false" aria-controls="panel-2" id="tab-2" tabindex="-1">
Second Tab
</button>
</div>
<div id="panel-1" role="tabpanel" tabindex="0" aria-labelledby="tab-1">
<p>Content for the first panel</p>
</div>
<div id="panel-2" role="tabpanel" tabindex="0" aria-labelledby="tab-2" hidden>
<p>Content for the second panel</p>
</div>
</div>The aria-* attributes are part of the WAI-ARIA (Web Accessibility Initiative-Accessible Rich Internet Applications) suite. They are used to improve the accessibility of web pages. However, when we use an input element with a type attribute whose value is hidden, we imply that the element is invisible and has no interaction with the user. Therefore, it doesn’t make sense to add aria-* attributes to it.
To fix this issue, you need to remove the aria-* attributes from the input element with type=hidden. Here is an example:
<!-- Wrong code -->
<input type="hidden" name="referer" value="https://example.com" aria-invalid="false">
<!-- Correct code -->
<input type="hidden" name="referer" value="https://example.com">The aria-required attribute is used to indicate to screen reader users that a form input is required. As there is now in HTML a general required attribute which works with most user agents, it’s unnecessary to use both at the same time. In general, you can rely solely on the required attribute, unless you want to provide backwards compatibility on old screen reader software versions.
Example:
<form action="order.">
<!-- This will raise a warning on unnecesary attributes -->
<input id="city" name="city" aria-required="true" required />
<!-- You can use this instead -->
<input id="city" name="city" required />
</form>labelledby is not a valid attribute for the <svg> element. Perhaps you meant aria-labelledby?
The aria-labelledby attribute establishes relationships between objects and their label(s), and its value should be one or more element IDs, which refer to elements that have the text needed for labeling.
Example:
<div id="myBillingId">Billing</div>
<div>
<div id="myNameId">Name</div>
<input type="text" aria-labelledby="myBillingId myNameId"/>
</div>
<div>
<div id="myAddressId">Address</div>
<input type="text" aria-labelledby="myBillingId myAddressId"/>
</div>Due to an issue in the W3C validator, this is identified as an error but it’s not. This issue has been notified, and we’ll update our validator as soon as there’s a fix.
According to the WAI-ARIA 1.2 spec:
The aria-setsize property defines the number of items in the current set of listitems or treeitems. Not required if all elements in the set are present in the DOM.
Authors MUST set the value of aria-setsize to an integer equal to the number of items in the set. If the total number of items is unknown, authors SHOULD set the value of aria-setsize to -1.
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.