1. Browsing the web #

Created Saturday 27 March 2021

Browsing the web #

Browsing the web? This is* “*trivial”. Yes, using is. But we cannot think of optimization without knowing these details.

First connection to a website #

• The URL is sent to the DNS, through the ISP(your Internet company).
• The DNS sends an IP address(the physical device’s address). This identifies the server(computer owned by the website) address. Your device also has an IP address.
• You communicate directly with the server now. You are still using going through the ISP, but a DNS is not required in between.

DNS is a system, as well as a server. Watch here.

How does the website load #

• You request the website(server) for a page. The default page is called the “landing page”.
• The server sends 3 kinds of files for the webpage:
  1. HTML
  2. JS
  3. CSS

Note: Media files like images, videos, PDF etc are also recieved.

• The browser reads the files and renders the webpage.

What do the files do? #

• HTML - defines basic structure of the page. Relative locations of paragraphs, quotes, buttons, videos, images etc are defined in this file.
• CSS - defines styling. - defines the font, color, styling and behavior of the parts defined by HTML.
• JavaScript - adds interactivity to the page. It can manipulate page elements.
• Media files are places as per the 3 files.

What happens when a new page is requested #

Naive way:

• You request for the new page.
• The server sends the relevant files.

Efficient way:

• The server actually sent many webpages at once, and the browser stored(cached) them.
• So the JS file loads the new page from the files cached before.
• This way the server has to only send files that are not in cache.
• This saves time and data resources, and makes the site fast.