Introduction
Cumulative Layout Shift (CLS) is a Core Web Vitals metric that measures the visual stability of a web page. High CLS scores can result in a poor user experience, as content unexpectedly shifts around the screen. In this article, we will discuss what CLS is, why it’s important, and how you can improve it on your website.
What is Cumulative Layout Shift (CLS)?
CLS measures the sum of layout shifts that occur during the entire lifespan of a page. A layout shift occurs when a visible element on the page changes its position from one frame to another. CLS quantifies the total amount of unexpected layout changes that can be disruptive to the user experience.
Why CLS Matters
CLS is important for several reasons:
User experience: High CLS scores can result in a frustrating and confusing experience for users, as content moves around the screen unexpectedly. This can lead to accidental clicks and difficulty in interacting with the page.
SEO: As one of the Core Web Vitals, CLS plays a role in determining your website’s search engine ranking. Optimizing CLS can help improve your search visibility and drive more organic traffic.
How to Improve CLS
Specify dimensions for images and embeds: Provide width and height attributes for images, videos, and other embedded content to prevent layout shifts as they load.
Reserve space for ads and dynamic content: Avoid inserting ads or dynamic content without reserving adequate space for them, as this can cause unexpected layout shifts.
Use CSS aspect ratio boxes: Using CSS aspect ratio boxes can help maintain the aspect ratio of responsive elements and prevent layout shifts as the page loads.
Avoid using “transform” animations for content that affects layout: When animating elements, use CSS properties like “opacity” and “transform” that do not trigger layout changes, as this can help minimize layout shifts.
Conclusion
Cumulative Layout Shift is an essential metric for evaluating your website’s visual stability and user experience. By understanding what CLS is and implementing optimization strategies, you can improve your website’s layout stability, enhance the user experience, and potentially boost your search engine rankings.
