Customized tooltips

Summary

Principle.
Core HTML base.
ARIA roles, states and properties.
Keyboard interaction.
Expected behavior.
Note.

Principle

Tooltips are messages that allow the user to obtain additional information about an item. The message is displayed on hover and also when keyboard focus is on the element.

A tooltip is “customized using ARIA” when it is not built using the standard HTML code as found in the specification, which is the title attribute.

This code is based on the “Tooltip” design pattern found in the ARIA Authoring Practices Guide (APG) of the W3C.

Core HTML base

<a href="#" aria-describedby="extrainfo">[Link text]</a>
<div role="tooltip" id="extrainfo">[Content of the tooltip]</div>

ARIA roles, states and properties

tabindex="0" must be applied to the element which will cause the tooltip to be displayed, if the tooltip is not reachable by default using the keyboard.
role="tooltip" must be applied to the tooltip container.
The element which triggers the tooltip must be programmatically associated with the tooltip via the aria-describedby attribute:
- The container of the tooltip must have an id attribute set to a unique value.
- The element that triggers the tooltip must contain an aria-describedby attribute set to the value of the id attribute of the container for the tooltip.

Keyboard interaction

`Esc`

When the tooltip is visible, this key hides the tooltip.

Expected behavior

The tooltip must be displayed when the triggering element:
- Is hovered over by the mouse.
- Receives keyboard focus.
The tooltip must be hidden when the triggering element:
- Is not hovered over.
- Does not have keyboard focus.
Hitting the Esc key hides the tooltip.
The tooltip must remain visible as long as the mouse is hovering over the triggering element.
When the tooltip is hidden, it must have display: none; and/or visibility: hidden;. Or alternatively, it can be removed from the source code.

Note

The major advantage of a custom tooltip over its standard HTML counterpart (title attribute) is that the custom tooltip is also accessible for keyboard users.