06. How the Web Works? | Code with Mosh

Summary

In this lesson, we explore how the web functions when you type a URL into your browser. It begins with a request sent from the browser (client) to the web server using the HTTP protocol. The server responds with an HTML document, which the browser reads to construct the Document Object Model (DOM). The browser then retrieves additional resources like images and stylesheets. Finally, all the content is rendered on the screen. This step-by-step process highlights the client-server model and the critical role of HTTP in web communication.

Takeaways

• 😀 A URL (Uniform Resource Locator) is the address of a website that helps locate resources on the internet, such as web pages, images, and videos.
• 😀 The process of visiting a website involves two main components: the browser (client) and the server that hosts the website (server).
• 😀 The client-server model means that the browser (client) requests information from the server, which responds by providing the requested resource.
• 😀 HTTP (Hypertext Transfer Protocol) is the language that browsers and servers use to communicate, while HTTPS is the secure version of HTTP that encrypts the data exchanged.
• 😀 When a browser sends a request, it uses HTTP to ask the server for a specific resource, often the homepage of the website (e.g., 'index.html').
• 😀 HTTP requests contain details like the requested resource, the website's address (host), and the preferred language of the browser.
• 😀 An HTTP response from the server includes the requested resource (like HTML code), a status code (e.g., 200 OK), and content type (e.g., text/html).
• 😀 The browser reads the HTML response and builds a Document Object Model (DOM), which represents the structure and elements of the webpage.
• 😀 As the browser reads the HTML, it may find additional resources (like images or stylesheets), which prompts it to send more HTTP requests to fetch them.
• 😀 After retrieving all necessary resources, the browser renders the webpage, which means displaying it visually for the user to interact with.

Q & A

What is a URL and why is it important?

A URL (Uniform Resource Locator) is the web address used to locate a resource on the internet, such as a webpage, image, or video. It's essential because it helps browsers find and access resources across the web.

What is the client-server model in web development?

The client-server model is a communication system where the client (your browser) sends requests for resources, and the server (the computer hosting the website) responds by providing those resources.

What is HTTP and how does it function?

HTTP (Hypertext Transfer Protocol) is a protocol used for communication between the browser (client) and the web server. It allows clients to request resources and servers to send those resources back.

How is HTTPS different from HTTP?

HTTPS is the secure version of HTTP. It encrypts the communication between the client and server to ensure privacy and security, preventing data interception or tampering.

What does an HTTP request contain?

An HTTP request typically contains the method (such as GET), the resource being requested (e.g., `index.html`), the protocol version, the host (website), and optional headers like language preferences.

What is the significance of the status code in an HTTP response?

The status code in an HTTP response indicates the outcome of the request. For example, a `200 OK` status means the request was successful, while other codes like `404` indicate errors, such as a resource not being found.

What is the Document Object Model (DOM)?

The DOM is a programming interface that represents the structure of an HTML document. It organizes the webpage's elements (like text, images, and links) in a hierarchical model that browsers can manipulate to render the page.

Why does the browser send multiple HTTP requests for a webpage?

When rendering a webpage, the browser sends multiple HTTP requests to retrieve various resources, such as images, fonts, and scripts. This helps ensure that all elements of the page are loaded and displayed properly.

What happens after the browser receives the HTML response from the server?

Once the browser receives the HTML response, it reads the document, creates the DOM, and begins rendering the webpage. This involves fetching additional resources and displaying the content for the user.

What does it mean to 'render' a webpage?

Rendering a webpage means displaying it visually in the browser. This process involves interpreting the HTML, CSS, and other resources to present the content in a structured and styled manner on the screen.