The Powerful CSS not Selector

This article was originally posted on my personal blog.

The :not() CSS selector is a powerful addition to the pseudo-class toolbelt, allowing you to select elements that are omitted by its argument.

A basic :not() CSS Selector Example

Here’s an example. I have a few classes set up - one applies base styles for all buttons, one sets the styles of a primary button, and another determines what a primary disabled button should look like.

📢 I’m using SCSS in the example below to gain the benefit of class nesting and variables, but the application of the :not() selector is the same.

.button {
  border: none;
  padding: 1rem 2rem;
  border-radius: 0.5rem;
  cursor: pointer;
    margin-top: 1rem;
}

.button--primary {
  background: $button--primary;
  color: white;
}

.button--disabled {
  background: $button--disabled;
  cursor: auto;
}

In order to align with accessibility, it’s important that the background of the button changes when in hover state. That’s simple enough; here’s the change.

.button--primary:hover {
  background: $button-primary-hover;
}

But, after adding the :hover selector, we run into a problem. Try hovering over the disabled button and notice that the background changes as if we were hovering over an active primary button.

How do we get around this? The :not() selector makes this an easy fix, allowing the change to only affect primary buttons that are not disabled!

.button--primary:hover:not(.button--disabled) {
  background: $button-primary-hover;
}

📢 Instead of using a class to determine if the button is disabled, I could have opted to use the :disabled attribute. I think the examples above are a bit easier to follow.

Browser Compatibility for the :not Selector

Thankfully, the :not() selector is supported by most major browsers.

Check out caniuse.com to see the exceptions.

Conclusion

In this article, we briefly discussed the :not() selector and saw a real-world example. A variety of options open up when using this selector - what applications can you think of?