My site's LCP and CLS scores are dragging down our SEO performance. We use a lot of third-party scripts and heavy images. What are the specific JavaScript techniques I should implement to improve these metrics without stripping away essential site functionality or user tracking?
3 answers
To improve Core Web Vitals, you should prioritize loading critical scripts. Use the defer or async attributes for non-essential JS and implement "Partytown" to run third-party scripts (like analytics) in a web worker. For CLS, ensure you are reserving space for dynamic content and images by setting explicit dimensions. For LCP, minimize the main thread work by splitting your code into smaller chunks. These technical adjustments signal to Google that your site provides a stable and fast user experience, which is a direct ranking factor in their current search algorithm.
Have you audited your site using the Chrome DevTools Performance tab to see which specific scripts are blocking the main thread during load?
Using a library like next/image or native lazy loading for images can significantly boost your LCP score without much effort.
Great point Elizabeth; optimizing images often yields the biggest "bang for your buck" when trying to hit those green Core Web Vitals targets.
Brian, that's a great tip. Using the Coverage tab specifically helps identify "dead code" in your bundles. Removing unused JavaScript is one of the fastest ways to improve the Total Blocking Time (TBT) and speed up the overall page load.