Recently, Google published a post about Core Web Vitals that found that mobile users only keep their attention on a web page for 4-8 seconds at a time. Core Web vitals are metrics designed to measure site performance in human experience. The open-source Chromium project announced these web vitals in May 2020 and they are adopted across Google products. Core Web Vitals measure how long it takes to complete the script functions needed to paint the above-the-fold content.