Note from 28 June 2021

Rhetorical WebPerf question: is it better to have a low or stable Cumulative Layout Shift? 😅

CLS increases a lot, but becomes stable


  1. I have a client site with a header that is hidden when the user scrolls down, but shown again when the user scrolls up, which seems pretty comon nowadays.

    This triggers some CLS, even if the hide/show is done in less than 500 ms, as “continuous interactions such as scrolls, drags, or pinch and zoom gestures are not considered ‘recent input’”. 😞

  2. screenshot of Priority Hints and optimizing LCP

    Kevin Farrugia

    Priority Hints and optimizing LCP

    Increasing the priority of a resource usually comes at the cost of another resource, so Priority Hints should be used sparingly. However, if the browser is queuing your LCP image, I recommend you experiment with Priority Hints to see if you can reduce this waiting time and improve your LCP.

  3. Of course we don't work on performance improvements only for Google, but the Search Console is our clients' main concern, so when it shows such a graph, it's satisfying for everyone! 🎉

    Screenshot of a graph from the Google Search Console showing a great improvement of Core Web Vitals