Mobile CLS Optimization Strategies for Better User Experience

To optimize Mobile Cumulative Layout Shift (CLS) for a better user experience, focus on stabilizing page layout by:

1. Defining explicit dimensions for all media elements such as images, videos, and iframes using width, height, or the CSS aspect-ratio property. This reserves space before content loads, preventing unexpected shifts.

2. Reserving space for dynamic content like ads or injected elements by using placeholders or minimum height containers. Avoid inserting new content above existing content unless triggered by user interaction, as this causes disruptive layout shifts.

3. Managing font loading carefully to prevent text resizing shifts. Use font-display strategies and preload critical fonts to reduce layout changes caused by late font swaps.

4. Using smooth transitions and animations to provide visual context for expected layout changes, improving perceived stability without negatively impacting CLS.

5. Leveraging browser features like the back/forward cache (bfcache) to ensure pages restore instantly without layout shifts when users navigate back and forth, reducing repeated CLS events.

6. Applying lazy loading correctly by defining dimensions for lazy-loaded images and videos to avoid layout shifts during loading.

7. Prioritizing image loading over rendering tasks to prevent intermediate frames without images that cause layout shifts.

8. Ignoring layout shifts during user interactions like dragging or resizing on desktop, which can also be relevant for mobile touch interactions, to avoid penalizing expected shifts.

By implementing these strategies, mobile websites can achieve CLS scores of 0.1 or less, significantly enhancing user experience by providing visually stable pages during loading and interaction.