Introduction to Web Concepts
Understand URLs, browsers, HTTP, and DNS — the invisible infrastructure behind every click.
Step 1 of 5
URLs: the addresses of the web
Every page on the web has a unique address called a URL (Uniform Resource Locator). When you type https://www.youtube.com/watch?v=abc123 into your browser, each part of that URL has a specific meaning:
- https:// — the protocol (how to communicate). Like choosing to send a letter vs. a phone call.
- www.youtube.com — the domain name (which server to talk to). Like a street address.
- /watch — the path (which page on that server). Like an apartment number within a building.
- ?v=abc123 — the query string (extra info). Like a note attached to the letter: 'I want video abc123.'
URLs were invented so that every resource on the web — every page, every image, every video — could have one unique, shareable address. You can send a URL to anyone in the world, and they will see the exact same resource. This was a revolutionary idea: before the web, sharing a specific document on a remote computer was extremely difficult.
Think of it this way: A URL is like a postal address. The country is the protocol, the city and street is the domain name, the house number is the path, and any special delivery instructions are the query string. Just like a postal address uniquely identifies one mailbox in the world, a URL uniquely identifies one resource on the web.
Web Standard
The 'S' in HTTPS stands for 'Secure.' HTTPS encrypts data between your browser and the server so nobody in between can read it. Modern browsers warn you when a site uses plain HTTP (without the S). Always look for HTTPS, especially when entering passwords or payment info.
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