Understanding Success Criterion 1.4.13: Content on Hover or Focus | WAI | W3C Skip to content

Understanding SC 1.4.13:Content on Hover or Focus (Level AA)

In brief

Objective
More users can perceive and dismiss non-persistent content
Author task
If hover or focus causes content changes, ensure interaction is predictable

Intent

Additional content that appears and disappears in coordination with keyboard focus or pointer hover often leads to accessibility issues. Reasons for such issues include:

  1. the user may not have intended to trigger the interaction
  2. the user may not know new content has appeared
  3. the new content may intefere with a user's ability to do a task

Examples of such interactions can include custom tooltips, sub-menus and other nonmodal popups which display on hover and focus. The intent of this success criterion is to ensure that authors who cause additional content to appear and disappear in this manner must design the interaction in such a way that users can:

  • perceive the additional content AND
  • dismiss it without disrupting their page experience.

There are usually more predictable and accessible means of adding content to the page, which authors are recommended to employ. If an author does choose to make additional content appear and disappear in coordination with hover and keyboard focus, this success criterion specifies three conditions that must be met:

  • dismissable
  • hoverable
  • persistent

Each of these is discussed in a separate section.

Dismissable

The intent of this condition is to ensure that the additional content does not interfere with viewing or operating the page's original content. When magnified, the portion of the page visible in the viewport can be significantly reduced. Mouse users frequently move the pointer to pan the magnified viewport and display another portion of the screen. However, almost the entire portion of the page visible in this restricted viewport may trigger the additional content, making it difficult for a user to pan without re-triggering the content. A keyboard means of dismissing the additional content provides a workaround.

Alternatively, low vision users who can only navigate via the keyboard do not want the small area of their magnified viewport cluttered with hover text. They need a keyboard method of dismissing something that is obscuring the current focal area.

Two methods may be used to satisfy this condition and prevent such interference:

  1. Position the additional content so that it does not obscure any other content including the trigger, with the exception of white space and purely decorative content, such as a background graphic which provides no information.
  2. Provide a mechanism to easily dismiss the additional content, such as by pressing Escape.

For most triggers of relatively small size, it is desirable for both methods to be implemented. If the trigger is large, noticing the additional content may be of concern if it appears away from the trigger. In those cases, only the second method may be appropriate.

The success criterion allows for input error messages to persist as there are cases that require attention, explicit confirmation or remedial action.

Hoverable

The intent of this condition is to ensure that additional content which may appear on hover of a target may also be hovered itself. Content which appears on hover can be difficult or impossible to perceive if a user is required to keep their mouse pointer over the trigger. When the added content is large, magnified views may mean that the user needs to scroll or pan to completely view it, which is impossible unless the user is able to move their pointer off the trigger without the additional content disappearing.

Another common situation is when large pointers have been selected via platform settings or assistive technology. Here, the pointer can obscure a significant area of the additional content. A technique to view the content fully in both situations is to move the mouse pointer directly from the trigger onto the new content. This capability also offers significant advantages for users who utilize screen reader feedback on mouse interactions. This condition generally implies that the additional content overlaps or is positioned adjacent to the target.

Persistent

The intent of this condition is to ensure users have adequate time to perceive the additional content after it becomes visible. Users with disabilities may require more time for many reasons, such as to change magnification, move the pointer, or simply to bring the new content into their visual field. Once it appears, the content should remain visible until:

  • The user removes hover or focus from the trigger and the additional content, consistent with the typical user experience;
  • The user dismisses the additional content via the mechanism provided to satisfy the Dismissable condition; or
  • The information conveyed by the additional content becomes invalid, such as a 'busy' message that is no longer valid.

Additional Notes

  • This criterion does not attempt to solve such issues when the appearance of the additional content is completely controlled by the user agent. A prominent example is the common behavior of browsers to display the title  attribute in HTML as a small tooltip.
  • Modal dialogs are out of scope for this criterion because they must take keyboard focus and thus should not appear on hover or focus. Refer to Success Criterion 3.2.1, On Focus.
  • Content which can be triggered via pointer hover should also be able to be triggered by keyboard focus. Refer to Success Criterion 2.1.1, Keyboard.

Benefits

  • Users with low vision who view content under magnification will be better able to view content on hover or focus without reducing their desired magnification.
  • Users who increase the size of mouse cursors via platform settings or assistive technology will be able to employ a technique to view obscured content on hover.
  • Users with low vision or cognitive disabilities will have adequate time to perceive additional content appearing on hover or focus and to view the trigger content with less distraction.
  • users with low pointer accuracy will be able to more easily dismiss unintentionally-triggered additional content

Examples

Example 1: Dismissable Tooltip

Screenshot of a button with a mouse pointer over it, and a tooltip displayed below the button Screenshot of a button with a mouse pointer over it, and no tooltip
Figure 1 A tooltip is displayed below a LVTF button on hover so as not to obscure the button itself. It does however obscure content below the button (the next red button, called ~comment-zoom-content). To meet the Dismissible requirement, a user can press the Escape key to clear the tooltip without moving the mouse, as demonstrated in the second image.
Screenshot of a button with a focus indicator on it, and no tooltip
Figure 2 The button's tooltip also appears on focus and can be removed with the Escape key. The screen shot shows the same LVTF button with focus, but the tooltip has been dismissed and is no longer visible.

Example 2: Hoverable Tooltip

Screenshot of a button with a large mouse pointer over it, and a tooltip displayed below the button which is obscured by the large pointer Screenshot of a button with a tooltip below it, and a large mouse pointer at the bottom of the tooltip
Figure 3 A button's tooltip is displayed directly below it on mouse hover which can easily be obscured by a large pointer. The tooltip itself is able to be hovered so the mouse pointer can be moved down to its bottom edge in order to view the tooltip text.

Related Resources

Resources are for information purposes only, no endorsement implied.

Techniques

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this Success Criterion. However, it is not necessary to use these particular techniques. For information on using other techniques, see Understanding Techniques for WCAG Success Criteria, particularly the "Other Techniques" section.

Sufficient Techniques

Failures

The following are common mistakes that are considered failures of this Success Criterion by the WCAG Working Group.

Key Terms
assistive technology

hardware and/or software that acts as a user agent, or along with a mainstream user agent, to provide functionality to meet the requirements of users with disabilities that go beyond those offered by mainstream user agents

Note

functionality provided by assistive technology includes alternative presentations (e.g., as synthesized speech or magnified content), alternative input methods (e.g., voice), additional navigation or orientation mechanisms, and content transformations (e.g., to make tables more accessible).

Note

Assistive technologies often communicate data and messages with mainstream user agents by using and monitoring APIs.

Note

The distinction between mainstream user agents and assistive technologies is not absolute. Many mainstream user agents provide some features to assist individuals with disabilities. The basic difference is that mainstream user agents target broad and diverse audiences that usually include people with and without disabilities. Assistive technologies target narrowly defined populations of users with specific disabilities. The assistance provided by an assistive technology is more specific and appropriate to the needs of its target users. The mainstream user agent may provide important functionality to assistive technologies like retrieving Web content from program objects or parsing markup into identifiable bundles.

  • screen magnifiers, and other visual reading assistants, which are used by people with visual, perceptual and physical print disabilities to change text font, size, spacing, color, synchronization with speech, etc. in order to improve the visual readability of rendered text and images;
  • screen readers, which are used by people who are blind to read textual information through synthesized speech or braille;
  • text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech;
  • speech recognition software, which may be used by people who have some physical disabilities;
  • alternative keyboards, which are used by people with certain physical disabilities to simulate the keyboard (including alternate keyboards that use head pointers, single switches, sip/puff and other special input devices.);
  • alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations.
conformance

satisfying all the requirements of a given standard, guideline or specification
input error

information provided by the user that is not accepted

Note

This includes:

  1. Information that is required by the Web page but omitted by the user
  2. Information that is provided by the user but that falls outside the required data format or values
mechanism

process or technique for achieving a result

Note

The mechanism may be explicitly provided in the content, or may be relied upon to be provided by either the platform or by user agents, including assistive technologies.

Note

The mechanism needs to meet all success criteria for the conformance level claimed.
process

series of user actions where each action is required in order to complete an activity
relied upon

the content would not conform if that technology is turned off or is not supported

technology

mechanism for encoding instructions to be rendered, played or executed by user agents

Note

As used in these guidelines "Web Technology" and the word "technology" (when used alone) both refer to Web Content Technologies.

Note

Web content technologies may include markup languages, data formats, or programming languages that authors may use alone or in combination to create end-user experiences that range from static Web pages to synchronized media presentations to dynamic Web applications.

user agent

any software that retrieves and presents Web content for users
web page

a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent

Note

Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.

Note

For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a Web page.

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