The internet and the world wide web

The internet 互联网 and the web

• People mix these up, but they're different.
• The internet is the network; the web is something you use on it.
• We'll follow a web page from a typed URL 统一资源定位符 to your screen.

Internet, web, URL and browser

• The internet is the worldwide infrastructure — computers, cables and routers.
• The world wide web 万维网 (WWW) is the collection of websites you view over the internet (email is another internet service).
• A URL is a page's text address, in three parts: protocol 协议 · domain name 域名 · path (https://www.example.com/index.html).
• A web browser 网页浏览器 fetches pages and renders their HTML into what you see.

The internet is the worldwide network; the world wide web is one of the things you use on it.

How a web page reaches you

1. The browser needs the site's IP address, but a URL is a name.
2. It asks a DNS 域名系统 (domain name service), which stores the IP for each web address.
3. The DNS returns the matching IP address.
4. The browser contacts the web server 网页服务器 at that IP.
5. The server sends back the page's HTML, which the browser renders.

A router joins your home network to the internet and sends data to the right place

Cookies 缓存文件

• A cookie is a small text file a website stores on your device to remember things.
• A session cookie is deleted when you close the browser (e.g. a shopping basket).
• A persistent cookie is saved on the device, remembering you between visits (logins, preferences).

A cookie is a small text file stored on your computer

You've got it