06. How the Web Works? | Code with Mosh

00:04:51
https://www.youtube.com/watch?v=Z7lFJLPoNeY

Summary

TLDRThe video explains the process that takes place when you enter a website's URL and press enter in a web browser. It delves into the client-server model, where the browser (client) sends an HTTP request to retrieve data from the server. A URL, or Uniform Resource Locator, identifies the web resource, which could be an HTML document, images, or videos. The HTTP protocol facilitates communication over the internet. When a request is made, it uses HTTP or HTTPS if encrypted. This process begins with an HTTP request to the server, which returns an HTTP response. The response includes the requested resource, commonly an HTML document. Once the browser receives this document, it builds the Document Object Model (DOM) and sends additional HTTP requests to gather all required resources like images or stylesheets. Once all resources are received, the browser renders the page for viewing.

Takeaways

  • 🌐 Understanding how URLs work in the browser.
  • 📡 Explanation of the client-server model.
  • 🔗 Function of HTTP and HTTPS protocols.
  • 📧 Structure and purpose of HTTP requests and responses.
  • 🧩 Concept of Document Object Model (DOM).
  • 📜 Rendering process of a webpage by the browser.
  • 🖥 Detailed walkthrough when a URL is entered in a browser.
  • 📂 How browsers manage resource fetching using HTTP.
  • 🔍 The significance of status codes in HTTP responses.
  • 📷 Handling of additional resources like images and fonts.

Timeline

  • 00:00:00 - 00:04:51

    The lesson explores how web browsers and servers communicate through URLs in the client-server model. When a URL is entered in a browser, it sends an HTTP request to a web server, which responds with HTML, starting the webpage display process. This interaction follows the HTTP or HTTPS protocol, where the browser constructs a Document Object Model (DOM) from received HTML to render pages. Subsequent resources like images and fonts are fetched via parallel HTTP requests. Rendering refers to displaying the HTML content on the page.

Mind Map

Mind Map

Frequently Asked Question

  • What is a URL?

    A URL, or Uniform Resource Locator, is a way to locate a resource on the internet, such as a webpage, image, or video.

  • What is the client-server model?

    In the client-server model, the client requests a service and the server provides it. For example, a web browser acts as a client when it requests a webpage from a server.

  • What does HTTP stand for?

    HTTP stands for Hypertext Transfer Protocol. It's a protocol for communication between clients and servers on the internet.

  • What is HTTPS?

    HTTPS is HTTP with encryption, where the data exchanged between the client and server is encrypted for security.

  • What are HTTP requests and responses?

    An HTTP request is a message from a client to a server asking for a resource. An HTTP response is the message the server sends back to the client with the requested resource.

  • What is the DOM?

    DOM stands for Document Object Model. It is a representation of a webpage's structure constructed by the browser from an HTML document.

  • What happens when a browser renders a page?

    Rendering a page involves displaying the HTML document and associated resources, like images and fonts, that a browser fetches from a server.

  • What is included in an HTTP response?

    An HTTP response includes a status code, date and time, type of content, and the requested HTML document or other resources.

  • What does a status code in an HTTP response indicate?

    A status code, like 200, indicates the result of the HTTP request, such as 'successful' or 'okay'.

  • Why does a browser send multiple HTTP requests when loading a page?

    A browser sends multiple HTTP requests to fetch additional resources like images and scripts needed to fully display a webpage.

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  • 00:00:00
    [Music]
  • 00:00:04
    have you ever wondered how the web Works
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    in this lesson I'm going to tell you
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    exactly what happens the moment you type
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    the address of a website into your
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    browser and hit enter as part of this
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    we're going to talk about a few
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    important Concepts and terms that you
  • 00:00:18
    need to know as a web developer so let's
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    say we launch our browser and head over
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    to a website like
  • 00:00:24
    codewithc now this address that we have
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    in the browser address bar is called a
  • 00:00:28
    URL which is short for uniform resource
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    locator basically it's a way to locate a
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    resource on the Internet Resources can
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    be web pages also called HTML documents
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    they can be images video files fonts and
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    so on so we type the URL of a website
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    and hit enter what happens now well
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    there are two pieces involved here the
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    browser also called the client and the
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    computer or computers that host our
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    Target website we refer to these as web
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    servers or servers for short this is
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    what we call the client server model the
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    client requests a service the server
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    provides that service so our browser
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    sends a message to the server and says
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    hey give me the homepage of this website
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    this is kind of similar to how you send
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    your friend a text message you can think
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    of your phone as the client sending the
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    message and your friend's phone as the
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    server receiving the message now back to
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    our example this message is formatted
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    based on a protocol called HTTP or
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    hypertext transfer protocol you have
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    probably noticed it before but never
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    knew what it is in simple terms HTTP is
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    a language that clients and servers use
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    to talk to each other it's not a
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    programming language it's just a plain
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    textual language for communicating over
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    the Internet we also have https which is
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    HTTP with encryption so the messages
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    exchanged between the client and the
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    server are encrypted here is a
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    simplified example of an HTTP message
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    with this message the browser tells the
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    server what it's looking for so on the
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    first line it says that it wants to get
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    a page or a file called
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    index.html using HTTP version 1.1
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    index.html often represents the homepage
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    of websites on the second line we can
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    see the host that is cod with.com and on
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    the third line we can see the language
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    that the client can accept in this case
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    English now don't worry about memorizing
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    any of this all I want you to understand
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    here is that this message is structured
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    based on the HTTP protocol that clients
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    and servers understand so the server
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    receives this message it figures out
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    what the client is asking and then it
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    will send a message back to the client
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    the first message is called an HTTP
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    request and the second message is called
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    an HTTP response every data exchange
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    using the HTTP protocol involves two
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    messages a request and a response now
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    what is in the response here's a
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    simplified example on the first line we
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    see the version of HTTP protocol used
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    followed by a number which is the status
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    code 200 means successful or okay right
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    below that we can see the date and time
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    of the response next we can see the type
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    of content the server is sending back to
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    the client in this case text/html and
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    after that we can see the HTML code or
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    the HTML document that represents the
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    homepage of cod with.com of course the
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    actual HTML code is way longer now as
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    the browser reads this HTML document it
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    constructs what we call a Dom or a
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    document object model don't let this
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    fancy name scare you this is a model
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    that represents the objects or elements
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    in our HTML document what are these
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    elements all the building blocks of our
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    page like paragraphs of text images
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    links and other stuff you will see this
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    in action in the next lesson now as the
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    browser is reading this HTML document
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    that is returned from the server it
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    discovers references to other resources
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    in this document like images fonts and
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    other stuff each of these resources has
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    an address or a URL so for each resource
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    the browser sends a separate HTTP
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    request to the server to fetch that
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    resource many of these HTTP requests are
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    sent in parallel so we can see the page
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    as quickly as possible once the browser
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    has all the necessary resources it will
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    render the HTML document rendering an
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    HTML document means displaying it it's a
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    fancy technical term we use often so in
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    a nutshell our browser sends an HTTP
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    request to the server and receives an
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    HTTP response this HTTP response
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    contains an HTML document the browser
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    reads that HTML document to construct a
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    document object model and render the
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    page in the next lesson I'm going to
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    show you all of these steps in action
Tags
  • web development
  • client-server model
  • HTTP
  • browsers
  • web protocols
  • URL
  • HTML
  • internet
  • DOM
  • rendering