Browser rendering

Summary

The step-by-step process a browser follows to turn HTML, CSS and JavaScript into pixels on screen — parsing, building the DOM/CSSOM, layout, paint and composite. Understanding this pipeline helps explain layout shifts, slow first paint, JavaScript-induced delays, and why optimizing the critical rendering path improves perceived performance.

• 1Read about the Critical Rendering Path on web.dev. Then apply the idea in a small example so the theory becomes practical.
• 2Open Chrome DevTools' Performance tab and record a page load. Inspect at least one real example and note what each important field or stage represents.
• 3Learn why render-blocking CSS/JS slows down first paint.