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How can I reduce cls by reserving space for dynamic ads or images?

Asked on Sep 27, 2025

Answer

To reduce Cumulative Layout Shift (CLS) caused by dynamic ads or images, it's essential to reserve space for these elements in advance. This can be achieved by defining specific dimensions for the ad or image containers in your CSS.

Example Concept: CLS can be minimized by setting explicit width and height attributes for images and ads. This ensures that the browser allocates the correct amount of space during the initial page load, preventing unexpected shifts when the content is loaded. Using CSS to define these dimensions for containers helps maintain layout stability.

Additional Comment:

Use CSS to set a fixed size for ad containers, even if the ad content is loaded asynchronously.
For responsive images, use the "srcset" attribute to define multiple image sizes and the "sizes" attribute to specify the image's display size.
Consider using aspect-ratio CSS property for flexible yet stable image sizing.
Regularly audit your site with tools like Lighthouse to identify and address CLS issues.

✅ Answered with Core Web Vitals best practices.

Ask any question about Performance here... and get an instant response.

How can I reduce cls by reserving space for dynamic ads or images?

Asked on Sep 27, 2025

Answer

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