The Open Web · Web Dev 1 · Learn the Web

The Open Web

World Wide Web

Tim Berners-Lee—1990 Invented at CERN for research documents

Specialized computers

Web servers—just serve websites
Chat servers
File servers
etc.

Connected computers

Each with a unique name—the IP Address

127.0.0.1
2001:0db8:85a3:0000:0000:8a2e:0370:7334

IPs are for computers

IP addresses are confusing for humans

Domains, like github.com, are for us

DNS

(Domain Name System)

Maps Domains ⬌ IPs

But your computer does know how to contact the DNS…

Your computer sends a message to the DNS and says, “Hey DNS, I’m looking for ‘google.ca’ can you tell me where that is?”
The DNS responds one of two ways:
- “Yes, the IP address is 8.8.8.4”
- or “No, try this other DNS that might know about ‘google.ca’; its IP address is 4.4.4.2”

All of this usually happens really quickly, we’re talking milliseconds here. Your computer even keeps a cache/history of all the domain-to-IP mappings so it doesn’t have to look them up in the future

And all the DNS computers regularly synchronize themselves all over the world

Websites are lots and lots of files…

HTML
CSS
JavaScript
Images
Video

Each downloaded separately

Performance matters

The more files the slower your website

Performance is the most important design constraint