Break a URL into scheme, host, port, path, query, and fragment, then trace how the browser uses the host to find an IP address through DNS. Follow the secure setup step where HTTPS uses TLS before any page data is exchanged.

Read a real HTTP exchange as a browser would: method, request headers, response status, response headers, and body. Reason through common outcomes like 200 OK, 301/302 redirects, 404 Not Found, and cached responses using Cache-Control or ETag.

Apply the previous explanations in a guided problem.

Trace how a server handles the requested path by returning a static file, running application code, calling a database or API, redirecting, or sending an error. Compare what the browser asks for with what the server is responsible for producing.

Follow how the browser turns incoming HTML bytes into the DOM and discovers more work: CSS files, images, fonts, scripts, and links with relative URLs. Predict why one page load usually becomes many network requests.

Apply the previous explanations in a guided problem.

Check your understanding with a short quiz.

Trace how CSS becomes the CSSOM, combines with the DOM, and moves through style calculation, layout, paint, and compositing. Recognize the role of browser engines such as Blink, Gecko, and WebKit in turning page structure into pixels.

Reason through when JavaScript runs during page loading and how it can read or change the DOM, fetch more data, handle events, or delay rendering. Compare plain scripts, defer scripts, and module scripts at a high level.

Apply the previous explanations in a guided problem.

Use the browser’s Network panel to connect the whole trip to evidence: URLs, DNS and connection timing, status codes, file types, sizes, caching, and load order. Diagnose simple failures like a missing file, blocked request, redirect loop, or slow resource.

Check your understanding with a short quiz.

Review this chapter with practice based on your mistakes.