Overview
Cumulative Layout Shift (CLS) is a metric Google uses to quantify how much a webpage's content shifts during the loading phase. It is a crucial aspect of web performance and user experience. When elements on a page move around unexpectedly as additional content gets loaded, it can lead to a frustrating experience for users, potentially causing accidental clicks or difficulty reading content. CLS scores are calculated by summing every unexpected layout shift that occurs during the lifespan of the page. A lower CLS score indicates a more stable and user-friendly experience, with Google recommending a CLS of 0.1 or lower for a good user experience. This metric is part of Google's Core Web Vitals, a set of factors that Google considers essential in a webpage's overall user experience.
Freestar's Solution
Freestar's CLS solution file seeks to mitigate CLS. For the ads to be CLS compliant, we must set a fixed height on the ad slot itself. We set that height for the largest size configured for that specific unit.
For information on using the Freestar CSS file, please see the installation section.