To fix web performance delays related to browser painting—such as First Paint (FP), First Contentful Paint (FCP), and Largest Contentful Paint (LCP)—you must clear the browser’s main thread and eliminate render-blocking resources. When the main thread is blocked by heavy scripts or complex styles, the browser cannot calculate layouts or draw pixels to the screen, resulting in severe visual delays. 🚀 1. Eliminate Render-Blocking Resources
The browser will not paint anything until it finishes downloading and parsing all scripts and stylesheets found in the HTML .
Defer or Async non-critical JavaScript: Use the defer attribute on script tags so they download in the background and execute after the page layout is parsed.
Inline critical CSS: Extract the minimal CSS needed to render the visible portion of the page (above-the-fold) and place it directly inside a