tags : Web Development,Web Performance
Core Web Vitals
Core Web Vitals is a subset of Web Vitals(3 metrics)
- Loading: Largest Contentful Paint (LCP)
- LCP measures the time it takes to get the largest element on the page visible within the viewport.
- Interactivity: First Input Delay (FID)
- It is the perception of an end user’s experience while interacting with a web page.
- FID requires real user data and cannot be measured in the lab (e.g. Google Lighthouse).
- the
Total Blocking Time (TBT)metric is lab-measurable and captures issues that affect interactivity.
- Visual stability: Cumulative Layout Shift (CLS)
- CLS is a measure of your site’s overall layout stability.
- CLS occurs when elements have been shifted after initially being rendered by the DOM.
Other metrics
- First Contentful Paint (FCP): Measures the time from when the page begins to load to when the first element is rendered on screen.