M

MLOG

English

A comprehensive guide to implementing accessible tooltips using hover and focus states, ensuring usability for all users including those with disabilities.

Tooltip Implementation: Hover and Focus Accessible Information

Tooltips are small, contextual help messages that appear when a user hovers their mouse pointer over or focuses on an element. They can provide additional information, clarify the purpose of an element, or offer hints on how to use a feature. However, tooltips can easily become accessibility nightmares if not implemented correctly. This guide outlines best practices for creating tooltips that are usable by everyone, including users with disabilities.

Why Accessibility Matters for Tooltips

Accessibility isn't just about compliance; it's about creating a better user experience for everyone. When tooltips aren't accessible, it can exclude users who rely on assistive technologies like screen readers, keyboard navigation, or speech input. Consider these scenarios:

By following accessibility best practices, we can ensure that tooltips enhance rather than hinder the user experience for all.

Key Principles for Accessible Tooltips

The following principles are crucial for creating accessible tooltips:

  1. Provide alternative access: Ensure tooltips are accessible via both hover and keyboard focus.
  2. Use ARIA attributes: Use ARIA (Accessible Rich Internet Applications) attributes to properly identify and describe tooltips to assistive technologies.
  3. Manage focus: Control where focus goes when a tooltip is displayed and hidden.
  4. Ensure sufficient contrast: Provide enough color contrast between the tooltip text and background.
  5. Allow sufficient time: Give users enough time to read the tooltip content.
  6. Make them dismissable: Provide a clear way to dismiss the tooltip.
  7. Avoid overuse: Use tooltips sparingly and only when necessary.

Implementation Techniques

1. Using Hover and Focus

The most critical aspect of accessible tooltips is ensuring they are accessible to both mouse and keyboard users. This means the tooltip should appear both on hover and when the element receives focus.

HTML:

<a href="#" aria-describedby="tooltip-example">Example Link</a>
<div id="tooltip-example" role="tooltip" style="display: none;">This is an example tooltip.</div>

CSS:

a:hover + div[role="tooltip"],
a:focus + div[role="tooltip"] {
  display: block;
  position: absolute;
  background-color: #f0f0f0;
  border: 1px solid #ccc;
  padding: 5px;
  z-index: 1000; /* Ensure the tooltip is on top */
}

Explanation:

JavaScript (Advanced Control - Optional):

While CSS can handle simple show/hide, JavaScript allows for more robust control, especially when tooltips are dynamically generated or need more complex behavior.

const link = document.querySelector('a[aria-describedby="tooltip-example"]');
const tooltip = document.getElementById('tooltip-example');

link.addEventListener('focus', () => {
  tooltip.style.display = 'block';
});

link.addEventListener('blur', () => {
  tooltip.style.display = 'none';
});

link.addEventListener('mouseover', () => {
  tooltip.style.display = 'block';
});

link.addEventListener('mouseout', () => {
  tooltip.style.display = 'none';
});

2. Using ARIA Attributes

ARIA attributes are essential for providing semantic information to assistive technologies. Here's a breakdown of key attributes:

Example:

<button aria-describedby="help-tooltip">Submit</button>
<div id="help-tooltip" role="tooltip" aria-hidden="true">Click here to submit the form.</div>

JavaScript (for aria-hidden):

const button = document.querySelector('button[aria-describedby="help-tooltip"]');
const tooltip = document.getElementById('help-tooltip');

button.addEventListener('focus', () => {
  tooltip.setAttribute('aria-hidden', 'false');
  tooltip.style.display = 'block';
});

button.addEventListener('blur', () => {
  tooltip.setAttribute('aria-hidden', 'true');
  tooltip.style.display = 'none';
});

button.addEventListener('mouseover', () => {
  tooltip.setAttribute('aria-hidden', 'false');
  tooltip.style.display = 'block';
});

button.addEventListener('mouseout', () => {
  tooltip.setAttribute('aria-hidden', 'true');
  tooltip.style.display = 'none';
});

3. Managing Focus

When a tooltip appears, it generally *should not* steal focus from the triggering element. Focus should remain on the element that triggered the tooltip. This ensures that keyboard users can continue navigating the page without unexpected interruptions.

However, there might be situations where you *want* to move focus to the tooltip, particularly if the tooltip contains interactive elements (e.g., links, buttons). In this case, ensure that:

In most cases, avoiding focus management within the tooltip itself is preferred for simplicity and usability.

4. Ensuring Sufficient Contrast

Color contrast is crucial for readability. Ensure that the text color in your tooltips has sufficient contrast against the background color. The Web Content Accessibility Guidelines (WCAG) recommend a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text (18pt or 14pt bold).

Use online contrast checkers to verify that your color choices meet accessibility standards. Examples of contrast checkers include:

Example (Good Contrast):

.tooltip {
  background-color: #000;
  color: #fff;
}

Example (Poor Contrast):

.tooltip {
  background-color: #fff;
  color: #eee;
}

5. Allowing Sufficient Time

Users need enough time to read the tooltip content. Avoid tooltips that disappear too quickly. While there's no magic number, aim for a minimum display time of a few seconds. Also, the tooltip should remain visible as long as the user is hovering over or has focused on the triggering element. If you need to dismiss the tooltip due to other events, provide an indicator that the tooltip will close.

If the tooltip content is lengthy, consider providing a way for the user to manually dismiss the tooltip (e.g., a close button or pressing the Escape key).

6. Making Them Dismissable

While tooltips often disappear automatically when the user moves their mouse away or removes focus, it's good practice to provide a clear way to dismiss them manually, especially for lengthy tooltips or tooltips containing interactive elements.

Methods for Dismissing Tooltips:

Example (Close Button):

<div id="my-tooltip" role="tooltip" aria-hidden="true">
  This is my tooltip content.
  <button onclick="hideTooltip()">Close</button>
</div>

Example (Escape Key):

document.addEventListener('keydown', function(event) {
  if (event.key === 'Escape') {
    hideTooltip(); // Replace with your actual hide tooltip function
  }
});

7. Avoiding Overuse

Tooltips should be used sparingly and only when they provide truly helpful information. Overusing tooltips can clutter the interface, distract users, and create a frustrating experience.

Alternatives to Tooltips:

Advanced Considerations

Dynamic Content

If your tooltip content is dynamically generated (e.g., loaded from an API or updated based on user input), ensure that the aria-describedby attribute and tooltip visibility are updated accordingly. Use JavaScript to manage these updates.

Positioning

Carefully consider the positioning of your tooltips. Avoid placing them in a way that obscures important content or causes layout shifts. Be mindful of different screen sizes and resolutions, and use CSS to ensure that tooltips are always visible within the viewport.

Mobile Devices

Tooltips traditionally rely on hover interactions, which are not available on touch-based devices. For mobile devices, consider using alternative interaction methods, such as:

Testing Your Tooltips

Thoroughly test your tooltips to ensure they are accessible to all users. Use a combination of manual testing and automated accessibility testing tools.

Testing Methods:

Internationalization (i18n) and Localization (l10n)

When developing tooltips for a global audience, keep internationalization and localization in mind:

Conclusion

Implementing accessible tooltips requires careful planning and attention to detail. By following the principles and techniques outlined in this guide, you can create tooltips that are usable by everyone, regardless of their abilities. Remember that accessibility is an ongoing process, so continue to test and refine your tooltips to ensure they meet the needs of all your users.

Resources