Scrolling Elements Into View

Although you should not mess with scrolling unless it is really necessary, scrolling an element into view is something that is needed from time to time. In my case, I recently wanted to scroll to the top of a table after a user clicked on the pagination underneath the table. One way to scroll to an element is to use the good old anchor link. While this is by far the most reliable and resilient option to scroll an element into view, it is not always possible and you have to rely on a bit of JavaScript instead. For a long time, the most reliable way to do this was to use jQuery and scroll the body to the top offset of the element you want to scroll into view:

$('html, body').scrollTop($(element).offset().top);

If you want to have a smooth scroll animation as well, you could use jQuery’s animate() function like so:

$('html, body').animate({
    scrollTop: $(element).offset().top
}, 500);

Here is a Codepen for this example:

See the Pen Scroll Into View – with jQuery by Matthias Ott (@matthiasott) on CodePen.

A Native, Modern Solution

While you could still do it that way, times have changed and modern browsers now come with native behaviors that can provide better alternatives to jQuery or other third-party scripts. This lets you save one dependency and, in the case of animate(), you might even end up with superior browser performance.

One way to scroll an element into view with native browser APIs is to rewrite the jQuery solution above so that it only uses element properties available in the browser:

// Get the size and position of our element in the viewport
var rect = element.getBoundingClientRect();
// The top offset of our element is the top position of the 
// element in the viewport plus the amount the body is scrolled
var offsetTop = rect.top + document.body.scrollTop;
// Now we can scroll the window to this position
window.scrollTo(0, offsetTop);

As you can see, we have achieved the same result with only three lines of code and both Element.getBoundingClientRect() and Window.scrollTo() have full browser support. But one thing is still missing: The animation. There are two ways we can add smooth scrolling to this solution. The first is to use the native CSS feature scroll-behavior:

html {
  scroll-behavior: smooth;
}

Again, have a look at the Codepen for this example:

See the Pen Scroll Into View – with CSS scroll-behavior: smooth by Matthias Ott (@matthiasott) on CodePen.

Nice! Still no need to mess around with JavaScript animations and we have a robust, progressively enhanced solution. Setting scroll-behavior to smooth will also work for anchor links, by the way. There is only one caveat: Some browsers, like Internet Explorer and Safari, don’t support scroll-behavior yet.

So if you want to support those browsers, too, you might want to use element.scrollIntoView instead:

element.scrollIntoView({ behavior: 'smooth' });

Browser support for scrollIntoView is good, but a few browsers like – you guessed it – IE and Safari don’t support the smooth behavior option. But fear not, there is a polyfill available that adds this functionality to those browsers.

Play around with this Codepen if you like:

See the Pen Scroll Into View – with element.scrollIntoView by Matthias Ott (@matthiasott) on CodePen.

Scroll Into View With GSAP

There is one more interesting option to achieve our scroll into view, and that is using the Greensock Animation Platform, aka GSAP, a JavaScript animation library. Let’s say you want to use hardware-accelerated animations in other corners of your site, too, then it can be a good idea to use GSAP to handle the scrolling as well. For one, you can stick to one solution and don’t have to jump from GSAP to element.scrollIntoView and back, but you will also be able to use a timeline in GSAP and easily combine the scroll animation with other animations.

The scroll position of the window can be animated in Greensock with the help of the ScrollToPlugin:

gsap.to(window, {duration: 0.75, scrollTo: element});

Another advantage of using Greensock is that you have more control over the animation timing and the easing functions, meaning the style of animation, and can make your animation really smooth and fine-tune it to your needs.

gsap.to(window, {
    duration: 1.2,  ease: "power4.inOut", scrollTo: element
});

Here, we are using a slightly slower animation with a nice, soft easing curve. Play around with this Codepen to try how the animation feels. If you are unsure which easing functions are available in GSAP, try the Ease Visualizer.

See the Pen Scroll Into View – with Greensock (GSAP) by Matthias Ott (@matthiasott) on CodePen.

What about A11y?

Depending on how much you scroll around, scroll around, scroll up, scroll up, and scroll down on the site, you will have to make sure that keyboard users don’t get lost. If you change the scroll position via JavaScript, keyboard focus might still not be updated. So when the user starts to navigate again, the site jumps back to where it was before you triggered the scrolling. Heather Migliorisi has written a nice post for CSS-Tricks about what to look for to make sure you build an accessible solution.

Another problem can be that people with a vestibular disorder can get sick when a site moves around too fast. And while those people can opt-out of playing video games that could become dangerous for them, visiting your site should not trigger motion sickness or an epileptic fit. One solution with good browser support is the prefers-reduced-motion media query (1, 2):

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion) {
  html {
	  scroll-behavior: auto;
	}
}

If you want the learn more about designing web animations for motion sensitivity, Val Head has written an excellent post for A List Apart.

And that’s it for today. If you have found other or even better ways to scroll an element into view, let me know. And if you found this post interesting, share it with your friends.

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This is the 39th post of my 100 days of writing series. You can find a list of all posts here.

~

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Baldur Bjarnason
“Scrolling Elements Into View · Matthias Ott – User Experience Designer” matthiasott.com/notes/scrollin…

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