Everyone loves a smooth web experience. The last thing you want is to click on a link and find yourself waiting forever while your browser struggles to load the page. But have you ever considered the metrics that dictate this user experience? Cumulative Layout Shift, or CLS, is one of those unsung heroes of web performance. In this article, we're going to dive into what CLS is, why it's important, and how it impacts your website's speed and usability.
What is Cumulative Layout Shift (CLS)?
CLS is a measure of the visual stability of a webpage. It quantifies how much unexpected layout shifting occurs as a page loads. These layout shifts can be due to various elements like images, videos, fonts, or even dynamically injected content. The lower your CLS score, the less layout shift occurs, and the better your users' experience.
What is Cumulative Layout Shift (CLS)?
Imagine this: you're reading an intriguing article online. You're just about to click a link when, out of nowhere, the content moves! You click, but instead of the link, you've just subscribed to a newsletter you didn't want. Frustrating, right? This experience is precisely what the Cumulative Layout Shift (CLS) metric tries to prevent.
CLS is a measure of the visual stability of a webpage. It quantifies how much unexpected layout shifting occurs as a page loads. These layout shifts can be due to various elements like images, videos, fonts, or even dynamically injected content. The lower your CLS score, the less layout shift occurs, and the better your users' experience.
Why Is CLS So Important?
Now, you might be thinking, "why should I care about CLS?" The answer is twofold: user experience and SEO.
In terms of user experience, high CLS scores can lead to "click frustration." This happens when elements on the page move around, causing users to click on the wrong things or struggle to interact with your site. It's a recipe for annoyed users and high bounce rates.
As for SEO, Google introduced CLS as a part of its Core Web Vitals—a set of metrics to evaluate page experience. And with the May 2021 update, these Core Web Vitals have become a ranking factor. Meaning, a lower CLS score can directly impact your site's ranking on search engine results pages (SERPs).
How CLS Impacts PageSpeed
CLS isn't just about ensuring your users don't click the wrong thing—it also impacts how quickly your page feels. The more a webpage shifts around during loading, the slower it seems to users, even if the actual load time is fast.
High CLS scores can lead to what's called "content jank," a noticeable stutter or jarring effect during scrolling or animations. This not only affects user experience but also makes your website seem slower than it actually is.
Understanding the Chaos
Now, let's not overlook the elephant in the room. When we mention that CLS can create chaos, we don't mean it'll cause your site to crash and burn. Rather, a high CLS score can make your site appear disorganized and haphazard to the end user, affecting their overall experience. High scores are usually a symptom of deeper issues, like a lack of responsive design or poorly optimized images and fonts. These are things that, when addressed, can improve your site's overall performance and usability.
FAQs
1. How can I measure my website's CLS? You can measure your website's CLS using tools like Google's PageSpeed Insights, Lighthouse, or Chrome DevTools.
2. How can I reduce my website's CLS score? To reduce your CLS score, ensure images and videos have specified dimensions, limit the number of dynamically injected content, and avoid inserting new content above existing ones.
3. What is a good CLS score? According to Google, a good CLS score is anything below 0.1.
4. Can a high CLS score affect my website's ranking on SERPs? Yes, as part of Google's Core Web Vitals, CLS can impact your website's ranking on SERPs.
5. Do I need to worry about CLS for mobile and desktop? Yes, you should consider CLS for both mobile and desktop versions of your site as the user experience is important on all devices.
Conclusion
In the grand scheme of web performance metrics, CLS might seem like just another acronym to remember. But in reality, it plays a crucial role in user experience and your website's performance. By understanding and improving your CLS score, you can offer a smoother, faster, and overall better browsing experience to your users. After all, in the world of web performance, every fraction of a second counts!
Next time you're caught in the whirlwind of webpage performance metrics, remember to consider CLS. Not only will it help make sense of the chaos, but it'll also provide you with a tangible way to improve your site's performance and SEO. Remember, a great user experience starts with a stable layout.