What Is Cumulative Layout Shift (CLS)?
Cumulative Layout Shift (CLS) is a metric that measures the visual stability of a webpage by calculating the extent of unexpected layout shifts that occur as content loads. These shifts can lead to a frustrating user experience, such as accidentally clicking on the wrong element when the layout moves unexpectedly.
The Importance Of Cumulative Layout Shift (CLS)
CLS impacts user experience by ensuring that content remains stable, avoiding accidental clicks and disruptions.
Types Of Cumulative Layout Shift (CLS)
- Good CLS: Less than 0.1.
- Needs Improvement: Between 0.1 and 0.25.
- Poor CLS: More than 0.25.
Examples Of Cumulative Layout Shift (CLS)
A button moving down because an image above it loads late.
Best Practices For Cumulative Layout Shift (CLS)
- Set explicit width and height for images and videos.
- Reserve space for ads and dynamic content.
- Avoid inserting new content above the viewport during loading.
Key Aspects Of Cumulative Layout Shift (CLS)
- User Trust: Stable layouts foster a positive perception.
- Visual Consistency: Ensures a polished and predictable interface.
- SEO Relevance: Part of Google’s Core Web Vitals.
Challenges For Cumulative Layout Shift (CLS)
- Managing dynamic content such as ads and personalized elements.
- Addressing layout shifts caused by third-party scripts.
Relevant Metrics
CLS score, calculated from impact fraction and distance fraction.
Conclusion
CLS is crucial for maintaining a visually stable and user-friendly website, directly affecting usability and SEO performance.
