Question
Answer and Explanation
Feature visibility significantly enhances tooltip accessibility by ensuring that users can perceive the tooltip's content regardless of their device, input method, or visual capabilities. Here's how:
1. Keyboard Navigation:
- Tooltips must be accessible via keyboard navigation. A visually hidden tooltip activated on `:hover` won’t help a keyboard user. Elements triggering the tooltip should receive focus and reveal the tooltip on focus, using `:focus` as well as `:hover`. This allows users who cannot use a mouse to access tooltip information.
2. Sufficient Contrast:
- Tooltip text should have sufficient color contrast against its background, complying with WCAG (Web Content Accessibility Guidelines) standards, generally a minimum ratio of 4.5:1 for small text. Users with low vision or color blindness depend on good color contrast to read text easily.
3. Appropriate Positioning:
- Ensure the tooltip appears within the viewport and does not obscure the activating element or other important content. Positioning should be adaptive to screen sizes. Overlapping elements make it hard for anyone, especially for assistive technology users, to get the context.
4. Avoid Hover-Only Activation:
- Relying solely on `:hover` is a poor accessibility practice. Implement `:focus` activation too. Mobile users and anyone using a touchscreen have no hover mechanism. Make sure tooltips can be activated by focusing with a keyboard or touch.
5. Avoid Timing Issues:
- Tooltips that disappear too quickly are hard for all users to access, especially people with cognitive disabilities, people using screen readers, or those with low vision that may be using a magnifier. Ensure tooltips stay visible long enough for the content to be read.
6. Semantic HTML:
- Use semantic HTML elements to markup tooltips, for example, using the `aria-describedby` attribute to connect the triggering element with the tooltip content to make it more accessible for assistive technologies, like screen readers. This clarifies context for the user. Additionally, make sure the tooltip is not focusable by default (e.g. `tabindex="-1"` ) to avoid tabbing into it.
7. Use of ARIA attributes:
- Use ARIA (Accessible Rich Internet Applications) attributes such as `aria-label` or `aria-describedby` to provide additional contextual information for assistive technologies. `aria-live="polite"` could notify a screen reader of the dynamic content.
8. Responsive Design:
- Make sure that your tooltips display well across devices. They should not get cut off, be too small on smaller screens, or cause scrolling issues.
By considering these points, developers can ensure tooltips are not only functional but also inclusive, improving the overall user experience for everyone.