JavaScript Study Guide
Modern frontend fundamentals: semantic HTML, Flexbox/Grid, DOM, events
and fetch - with examples
Complete Study Guide | Key Concepts | Examples | Practice Questions
, 1. How the Web Works
A browser requests a URL; DNS resolves it; the server responds with HTML, CSS and JS; the browser renders the
page. The critical rendering path is: parse HTML -> build DOM -> apply CSS -> layout -> paint.
- Frontend = what runs in the browser; backend = server logic and databases.
- Static sites serve fixed files; dynamic sites generate responses per request.
- DevTools (F12) is your lab: inspect elements, debug JS, monitor network requests.
- Responsive design: the same page adapts to phone, tablet and desktop via CSS.
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