📘 Client Side

🔹 What is Client Side?

The client side refers to all the operations that happen on the user’s device, typically in a web browser or mobile app. This is the environment where the user sees, interacts with, and experiences the application.


🔹 What Happens on the Client Side?

  • Rendering HTML and applying CSS

  • Running JavaScript logic

  • Handling user interactions (clicks, input)

  • Making requests to the server (fetch, XHR)

  • Showing data received from the server

  • Caching/storing small data (localStorage, cookies)


🔹 Example:

You open a website:

  1. Your browser sends a request to a server.

  2. The server sends HTML, CSS, and JS files.

  3. The browser (client) builds the UI, runs JS, and responds to your actions — all of this happens on the client side.


🔹 Core Technologies:

TechRole
HTMLStructure of the web page
CSSStyling and layout
JavaScriptDynamic behavior and logic
Browser APIsBuilt-in functions for interaction, storage, etc.
FrameworksReact, Vue, Angular for building UIs efficiently

🔹 Characteristics:

  • Executes in user’s browser

  • Visible and inspectable

  • Device-dependent (performance varies)

  • Doesn’t require internet for all actions (can work offline partially using Service Workers)


  • Server Side: Runs on backend (e.g., Node.js, Java, Python)

  • CSR (Client-Side Rendering): Entire UI is built on the client using JavaScript

  • SPA (Single Page Application): A type of web app that works entirely on the client side after initial load