Web Technologies

At A-Level you need to understand how web pages are constructed and served, the difference between client-side and server-side processing, and the roles of HTML, CSS, JavaScript, and server-side scripting languages.

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How the Web Works — A Quick Recap

1. The user enters a URL in the browser (or clicks a link).
2. The browser uses DNS to resolve the domain name to an IP address.
3. The browser sends an HTTP/HTTPS request to the web server.
4. The web server processes the request (possibly running server-side scripts and querying a database).
5. The server sends back an HTTP response containing HTML (and possibly CSS and JavaScript).
6. The browser renders the page — parsing the HTML, applying CSS styles, and executing JavaScript.

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HTML (HyperText Markup Language)

HTML defines the structure and content of a web page using elements enclosed in tags.

Key Concepts