0.5.5 Clients and Servers: The Browser

A Browser Is More Than a Window That Shows Pages

When you open a website, the browser does not usually begin with the complete webpage already stored inside it.

The browser acts as a client.

A client requests information or a service from another system.

A server receives that request and provides a response.

For the Web, the browser and web server form a common client/server interaction.

Client and Server Describe Roles

The words client and server describe roles in an interaction.

The client asks for something.

The server provides a response.

A simplified web interaction is:

Plain text
Browser client
      ↓ request
Web server
      ↓ response
Browser client

The browser then interprets the returned web information and presents it to the user.

The Browser Creates Requests

Suppose you enter a web address for a soccer club website.

The browser uses the address to determine what resource is being requested.

It then creates and sends a web request.

At this stage, you do not need to build that request manually.

Focus on the responsibility:

Browser/client responsibility: request a web resource and process the response for the user.

The Server Receives the Request

The server receives the request and determines how to respond.

Depending on the site, the server might:

The internal implementation can be complex.

For this module, the server's role can be kept simple:

Server responsibility: receive the request and send an appropriate response.

The Browser Interprets the Response

A response can contain information such as HTML.

The HTML may then refer to additional resources such as:

The browser interprets those resources and produces the visible page.

That gives a simplified flow:

Plain text
User enters URL
      ↓
Browser creates request
      ↓
Server processes request
      ↓
Server sends response
      ↓
Browser interprets response
      ↓
Browser displays webpage

Client Does Not Mean “Less Important”

Client and server are not rankings.

They are roles.

The browser has substantial work to do:

The server also performs important work.

The interaction succeeds because the responsibilities cooperate.

The Server Is Not the Website Screen

A user sees the page inside the browser.

The server usually does not send a picture of the completed browser window.

It sends web resources or data that the browser interprets.

That distinction connects directly to HTML and CSS.

The browser receives representations.

Then it turns those representations into the displayed page.

One Browser Can Communicate With Many Servers

The same browser can visit many different websites.

Its role as a client remains similar.

The destination server changes according to the requested URL.

Likewise, one server can respond to many clients.

This makes client/server a reusable communication model rather than a one-browser-to-one-server pairing.

A Soccer Website Example

Imagine you visit a team page.

The browser might request:

Plain text
https://example.com/wildcats

The server responds with the resource associated with that request.

The browser may then request additional files referenced by the page, such as:

Plain text
styles.css
team-photo.jpg

The displayed site can therefore involve several request/response exchanges.

The page feels like one experience to the user, but the underlying web interaction can involve multiple resources.

The Important Responsibility Split

Keep these roles clear:

User

Chooses where to navigate and interacts with the page.

Browser/client

Creates requests, receives responses, interprets web resources, and displays the result.

Server

Receives requests and provides responses.

The next activity follows this interaction as a sequence from entering a URL to seeing the webpage.