In the world of web performance, one of the most important metrics to pay attention to is Cumulative Layout Shift (CLS). CLS affects how users interact with your website, and if it is too high, it can lead to a poor user experience. In this article, we will discuss what CLS is, what causes the CLS issue on mobile, and how to optimize your website to keep your CLS score below 0.25.
Introduction to CLS: What is CLS and Why is it Important?
CLS is a metric used to measure the stability of visual content on a website. It is calculated by taking the sum of the individual layout shifts that occur during the page load. The higher the CLS score, the more unstable your website is, and the worse the user experience.
It is important to keep your CLS score low because users tend to be more frustrated when content on a page shifts around as it loads. If your CLS score is too high, users may have difficulty navigating your website and may leave your site before finishing what they were doing. This can lead to increased bounce rates and decreased conversions.
What Causes the CLS Issue (Mobile)?
The CLS issue on mobile is often caused by slow loading images, ads, third-party plugins, and web hosts. These can all contribute to a high CLS score, and they should be addressed in order to keep your score below 0.25.
Common Solutions to Keeping CLS Below 0.25 (Mobile)
There are several strategies you can use to keep your CLS score low on mobile. These include optimizing your CSS, JavaScript, images, ads, third-party plugins, web host, and website layout.
Optimizing CSS, JavaScript, and Images
Optimizing your CSS and JavaScript can help reduce the amount of layout shifts that occur during page load. You can do this by minifying your code, reducing the size of your files, and compressing images. Additionally, you should consider lazy loading images to reduce the amount of time it takes for them to load.
Optimizing Ads
If you are running ads on your website, it is important to optimize them for mobile. This means making sure that the ads are sized and optimized for mobile devices and that they are not blocking the content on the page. Additionally, you should consider using asynchronous ads to reduce the amount of time it takes for them to load.
Optimizing Third-Party Plugins
Third-party plugins can also contribute to a high CLS score. To reduce the amount of layout shifts caused by third-party plugins, you should consider using lazy loading to reduce the amount of time it takes for them to load. Additionally, you should make sure that the plugins you are using are optimized for mobile devices.
Optimizing Your Web Host
Your web host can also contribute to a high CLS score. To reduce the amount of time it takes for your website to load, you should consider using a content delivery network (CDN) to serve your website’s content. Additionally, you should look into using a web host with a fast server response time and optimized for mobile devices.
Optimizing Your Website Layout
Finally, you should consider optimizing your website layout for mobile devices. This means making sure that your website is responsive and that the content is laid out in a way that is easy to navigate on mobile devices. Additionally, you should make sure that all of your content is sized correctly for mobile devices.
Other Tips and Tricks
In addition to the strategies mentioned above, there are a few other tips and tricks you can use to keep your CLS score low. For example, you should consider using a performance budget to ensure that your website does not exceed a certain size, and you should make sure that you are using the latest version of your web browser. Additionally, you should make sure that you are using a caching plugin to reduce the amount of time it takes for your website to load.
Conclusion
In conclusion, CLS is an important metric to pay attention to when it comes to web performance. The CLS issue on mobile is often caused by slow loading images, ads, third-party plugins, and web hosts. To keep your CLS score below 0.25 on mobile, you should optimize your CSS, JavaScript, images, ads, third-party plugins, web host, and website layout. Additionally, you should consider using a performance budget, using the latest version of your web browser, and using a caching plugin. By following these tips, you can keep your CLS score low and ensure that your users have a great experience on your website.