CSS scroll-behavior

The scroll-behavior property

The scroll-behavior property tells the browser how to handle scrolling to anchor links within an element.

The default value, auto, does a hard jump like you’re used to. A value of scroll tells the browser to animate scrolling. There’s no way to specify easing, but it ties into the browser’s refresh rate to give you silky smooth animations.

/**
 * Enable smooth scrolling on the whole document
 */
html {
  scroll-behavior: smooth;
}

Here’s a demo

You can restrict it to specific elements if you want.

/**
 * Enable smooth scrolling on the #be-cool element
 */
#be-cool {
  scroll-behavior: smooth;
}

And if you want to disable it when someone uses their browser's "Find in page" function:

html:focus-within {
  scroll-behavior: smooth;
}

Accessibility concerns

Animations can cause issues for users who suffer from motion sickness and other conditions.

Fortunately, Windows, macOs, iOS, and Android all provide a way for users to specify that they prefer reduced motion. And all modern browsers (but not IE) provide a way to check for that setting in both CSS and JavaScript.

When using scroll-behavior, you should add a @media check for prefers-reduced-motion: reduce, and revert to the default auto.

/**
 * Disable smooth scrolling when users have prefers-reduced-motion enabled
 */
@media screen and (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

This prevents animated scrolling when users have specified that they’d prefer reduced motion.

Read more on MDN

Usage with JavaScript

// Scroll to specific values
// scrollTo is the same
window.scroll({
  top: 2500,
  left: 0,
  behavior: 'smooth',
})
// Scroll certain amounts from current position
window.scrollBy({
  top: 100, // could be negative value
  left: 0,
  behavior: 'smooth',
})
// Scroll to a certain element
document.querySelector('.hello').scrollIntoView({
  behavior: 'smooth',
})

Reference