This guide summarizes best practices for accessible tooltips, drawing from leading accessibility experts.

Understanding Tooltips

Tooltips offer brief text hints for UI elements, appearing on hover or focus. A concise definition: a non-modal overlay providing supplemental, descriptive text about a UI control. Crucially, accessible tooltips contain only descriptive text and no interactive elements. If interactivity is needed, use a dialog instead.

Two Tooltip Types

Tooltips serve two main purposes:

1. Icon Labeling: For brief labels (one or two words), use the aria-labelledby attribute. For additional context (e.g., a notification count), provide a space-separated list of IDs.

   <button aria-labelledby="notification-count notification-label">
       <span id="notification-count">3</span>
       <span id="notification-label">Notifications</span>
   </button>
   <div role="tooltip" id="tooltip-label">Notifications</div>

2. Contextual Description: For longer descriptions, use aria-describedby. The icon itself needs an accessible name, ideally included as hidden text within the element.

   <button aria-describedby="tooltip-description">
       <span style="display:none;">Notifications</span>
       <span aria-hidden="true">?</span>
   </button>
   <div role="tooltip" id="tooltip-description">View and manage notification settings</div>

Essential Do's and Don'ts

Do:

• Use aria-labelledby or aria-describedby appropriately.
• Employ the role="tooltip" even if current screen reader support is limited; future support may improve.
• Open on mouseover/focus, close on mouseout/blur.
• Prevent tooltip dismissal when hovering over its content.
• Enable keyboard closure via the Escape key (WCAG 1.4.13).

Don't:

• Use the title attribute (it has significant accessibility issues).
• Use aria-haspopup with role="tooltip" (tooltips are non-interactive).
• Place essential content within tooltips; screen readers might ignore associated ARIA attributes.

Limitations and Alternatives

Tooltips are inherently inaccessible to touch devices due to the lack of hover and focus. The best solution is often to integrate the label or description directly into the design. For extensive content (including interactive elements), consider a Toggletip or a <dialog></dialog> element. Toggletips, often indicated by an "i" icon, reveal information within a live region using the role="status".

<button aria-controls="toggletip-content">
    <span aria-hidden="true">?</span>
</button>
<div id="toggletip-content" role="status" aria-live="assertive" style="display:none;">This clarifies whatever needs clarifying</div>

For more on toggletips, refer to the resources below.

Further Reading

• Clarifying the Relationship Between Popovers and Dialogs (Zell Liew)
• Tooltips and Toggletips (Inclusive Components)
• Tooltips in the time of WCAG 2.1 (Sarah Higley)
• Short note on aria-label, aria-labelledby, and aria-describedby (Léonie Watson)
• Some Hands-On with the HTML Dialog Element (Chris Coyier)

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