CSS

Understanding the Difference Between `:focus` and `:focus-visible` in CSS

Published Nov 8, 2024

Updated Nov 8, 2024

3 min read

Understanding the Difference Between :focus and :focus-visible in CSS

I have learned my fair share about the importance of keyboard accessibility, so I know that visual indication of the focused element is very important. But the well-known :focus pseudo-class is not always the best fit for this job. That's where :focus-visible comes in. Let's look at the differences between these two pseudo-classes and explore the best practices for using them effectively.

What is the :focus Pseudo-Class?

The :focus pseudo-class is a CSS selector that applies styles to any element that receives focus, regardless of how that focus was triggered. This includes focus events from keyboard navigation, mouse clicks, and touch interactions.

Example Usage of :focus

button:focus {
  outline: 2px solid blue;
}

In this example, the button will display a blue outline whenever it is focused, whether the user clicks on it with a mouse, taps it on a touchscreen, or navigates to it using the keyboard.

What is the :focus-visible Pseudo-Class?

The :focus-visible pseudo-class is more specialized. It only applies styles to an element when the browser determines that the focus should be visible. This typically occurs when the user navigates via the keyboard or assistive technologies rather than through mouse or touch input.

Example Usage of :focus-visible

button:focus-visible {
  outline: 2px solid blue;
}

Here, the button will only show a blue outline when focused through keyboard navigation or another input method that usually requires visible focus indicators.

Key Differences Between :focus and :focus-visible

:focus

Behavior: Applies to any element that receives focus, regardless of the input method.
Use Cases: Ensures that all interactions with the element are visually indicated, whether by mouse, keyboard, or touch.

:focus-visible

Behavior: Applies styles only when the focus should be visible, such as using a keyboard or assistive technology.
Use Cases: Ideal for scenarios where you want to provide focus indicators only to keyboard and assistive technology users while avoiding unnecessary outlines for mouse and touch users, typically required by design.

Accessibility Implications

:focus

Pros:
Guarantees that all users can see when an element is focused, which is critical for accessibility.
Cons:
Can lead to a suboptimal experience for mouse users, as focus styles may appear unnecessarily during mouse interactions.

:focus-visible

Pros:
Enhances user experience by showing focus indicators only when necessary, thus keeping the interface clean for mouse and touch users.
Tailors the experience for keyboard and assistive technology users, providing them with clear visual cues.
Cons:
Additional considerations may be required to ensure that focus indicators are not accidentally omitted, especially in older browsers that do not support :focus-visible.
- There may be cases where you want to show focus indicators for all users, regardless of input method.

Best Practices for Using :focus and :focus-visible

To achieve the best accessibility and user experience, combining both :focus and :focus-visible in your CSS is often a good idea.

Combining :focus and :focus-visible

button:focus {
  outline: none; /* Remove default focus for all interactions */
 /* maybe some subtle general focus style */
}

button:focus-visible {
  outline: 2px solid blue; /* Only show outline when the element was interacted with via keyboard or assistive technology */
}

Here is a Stackblitz example of what such styling could look like for you to try out and play with.

Additional Tips

Test with Keyboard and Assistive Technology: Ensure that your web application is navigable using a keyboard (Tab, Shift + Tab, etc.) and that focus indicators are visible for those who rely on them. It's never a bad idea to include accessibility testing in your e2e testing suite.
Provide Clear Focus Indicators: Make sure that focus indicators are prominent and easy to see. A subtle or hard-to-spot focus indicator can severely impact accessibility for users who rely on keyboard navigation.

Conclusion

The :focus-visible pseudo-class offers a more refined way to manage focus indicators, improving accessibility and user experience, particularly for keyboard and assistive technology users. By understanding the differences between :focus and :focus-visible, and applying best practices in your CSS, you can create more accessible and user-friendly web applications.

Remember, accessibility should never be an afterthought. By thoughtfully applying focus styles, you ensure that all users, regardless of how they interact with your site, can easily navigate and interact.

This Dot is a consultancy dedicated to guiding companies through their modernization and digital transformation journeys. Specializing in replatforming, modernizing, and launching new initiatives, we stand out by taking true ownership of your engineering projects.

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About the author(s)

Jan Kaiser
Software engineer passionate about everything web-related. Particularly loves Angular, SCSS, TypeScript, soccer and dachshunds
@honzikec @honzikec

Exploring Open Props and its Capabilities

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Our site will look something like this: Open-props core does not contain any CSS reset. After all, it’s just a set of CSS variables. This is a good start regarding the document structure. Adding open props via CDN Let's add open-props to our project. To get started, add: ` This import will make the library's props available for us to use. This is a set of CSS variables. It contains variables for fonts, colors, sizes, and many more. Here is an excerpt of the content of the imported file: ` The :where pseudo-class wraps all the CSS variables declarations, giving them the least specificity. That means you can always override them with ease. This imported file is all you need to start using open props. It will provide a sensible set of variables that give you some constraints in terms of what values you can use, a palette of colors, etc. Because this is just CSS, you can opt-out by not using the variables provided. I like these constraints because they can help with consistency and allow me to focus on other things. At the same time, you can extend this by creating your own CSS variables or just using any value whenever you want to do something different or if the exact value you want is not there. We should include some styles to add a visual hierarchy to our document. Working with CSS variables Let's create a new file to hold our styles. ` And add some styles to it. We will be setting a size hierarchy to headings, using open props font-size variables. Additionally, gaps and margins will use the size variables. ` We can explore these variables further using open-props’ documentation. It's simple to navigate (single page), and consistent naming makes it easy to learn them. Trying different values sometimes involves changing the number at the end of the variable name. For example: font-size-X, where X ranges from 0 to 8 (plus an additional 00 value). Mapped to font-sizes from 0.5rem up to 3.5rem. If you find your font is too small, you can add 1 to it, until you find the right size. Colors range from 0-12: –red-0 is the lightest one (rgb(255, 245, 245)) while –red-12 is the darkest (rgb(125, 26, 26)). There are similar ranges for many properties like font weight, size (useful for padding and margins), line height and shadows, to name a few. Explore and find what best fits your needs. Now, we need to include these styles on our page. ` Our page looks better now. We could keep adding more styles, but we'll take a shortcut and add some defaults with Open Props' built in normalized CSS file. Besides the core of open props (that contains the variables) there’s an optional normalization file that we can use. Let's tweak our recently added styles.css file a bit. Let’s remove the rules for headings. Our resulting css will now look like this. ` And add a new import from open-props. ` Open props provides a normalization file for our CSS, which we have included. This will establish a nice-looking baseline for our styles. Additionally, it will handle light/dark mode based on your preferences. I have dark mode set and the result already looks a lot better. Some font styles and sizes have been set, and much more. More CSS Variables Let's add more styles to our page to explore the variables further. I'd like to give the pricing options a card style. Open Props has a section on borders and shadows that we can use for this purpose. I would also like to add a hover effect to these cards. Also, regarding spacing, I want to add more margins and padding when appropriate. ` With so little CSS added and using many open props variables for sizes, borders, shadows, and easing curves, we can quickly have a better-looking site. Optimizing when using the CDN Open props is a pretty light package; however, using the CDN will add more CSS than you'll probably use. Importing individual parts of these props according to their utility is possible. For example, import just the gradients. ` Or even a subset of colors ` These are some options to reduce the size of your app if using the CDN. Open Props with NPM Open Props is framework agnostic. I want my site to use Vite. Vite is used by many frameworks nowadays and is perfect to show you the next examples and optimizations. ` Let's add a script to our package.json file to start our development server. ` Now, we can start our application on port 5173 (default) by running the following command: ` Your application should be the same as before, but we will change how we import open props. Stop the application and remove the open-props and normalize imports from index.html. Now in your terminal install the open-props package from npm. ` Once installed, import the props and the normalization files at the beginning of your styles.css file. ` Restart your development server, and you should see the same results. Optimizing when using NPM Let's analyze the size of our package. 34.4 kb seems a bit much, but note that this is uncompressed. When compressed with gzip, it's closer to 9 kb. Similar to what we did when using the CDN, we can add individual sections of the package. For example in our CSS file we could import open-props/animations or open-props/sizes. If this concerns you, don't worry; we can do much better. JIT Props To optimize our bundled styles, we can use a PostCSS plugin called posts-jit-props. This package will ensure that we only ship the props that we are using. Vite has support for PostCSS, so setting it up is straightforward. Let's install the plugin: ` After the installation finishes, let's create a configuration file to include it. ` The content of your file should look like this: ` Finally, remove the open-props/style import from styles.css. Remember that this file contains the CSS variables we will add "just in time". Our page should still look the same, but if we analyze the size of our styles.css file again, we can see that it has already been reduced to 13.2kb. If you want to know where this size is coming from, the answer is that Open Props is adding all the variables used in the normalize file + the ones that we require in our file. If we were to remove the normalize import, we would end up with much smaller CSS files, and the number of props added just in time would be minimal. Try removing commenting it out (the open-props/normalize import) from the styles.css file. The page will look different, but it will be useful to show how just the props used are added. 2.4kB uncompressed. That's a lot less for our example. If we take a quick look at our generated file, we can see the small list of CSS variables added from open props at the top of our file (those that we use later on the file). 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Understanding the Difference Between `:focus` and `:focus-visible` in CSS

Understanding the Difference Between :focus and :focus-visible in CSS

What is the :focus Pseudo-Class?

Example Usage of :focus

What is the :focus-visible Pseudo-Class?

Example Usage of :focus-visible

Key Differences Between :focus and :focus-visible

:focus

:focus-visible

Accessibility Implications

:focus

:focus-visible

Best Practices for Using :focus and :focus-visible

Combining :focus and :focus-visible

Additional Tips

Conclusion

Jan Kaiser

You might also like

Exploring Open Props and its Capabilities

How to Run End-to-End Tests on Vercel Preview Deployments

Why is My React Reducer Called Twice and What the Heck is a Pure Function?

AI Leadership: Data-Driven Decision Making & Avoiding "Analysis Paralysis" with Jerry Reghunadh

Let's innovate together!

You might also like

Exploring Open Props and its Capabilities

How to Run End-to-End Tests on Vercel Preview Deployments

Why is My React Reducer Called Twice and What the Heck is a Pure Function?

AI Leadership: Data-Driven Decision Making & Avoiding "Analysis Paralysis" with Jerry Reghunadh