Curriculum
WebSockets in JavaScript are a modern communication technology that enables real-time, bidirectional communication between clients and servers over a single persistent connection. Understanding WebSockets Introduction in JavaScript helps beginners build live applications like chat systems, notifications, multiplayer games, stock dashboards, and scalable real-time web applications professionally.
Traditional web communication mainly uses:
In HTTP:
Problem:
Applications like:
Require:
Before WebSockets:
Problems with polling:
Modern applications require:
To solve this:
WebSockets provide:
WebSockets are widely used in:
Understanding WebSockets in JavaScript is essential for modern real-time application development.
WebSockets help developers:
Modern scalable applications heavily depend on:
A WebSocket is:
Unlike HTTP:
Both client and server can:
This creates:
| HTTP | WebSockets |
|---|---|
| Request-response model | Persistent communication |
| Stateless | Stateful connection |
| Multiple connections | Single connection |
| Slower for real-time apps | Faster real-time communication |
WebSockets improve:
Flow:
This process creates:
JavaScript provides:
Syntax:
const socket = new WebSocket("ws://localhost:3000");Where:
ws:// → WebSocket protocolwss:// → Secure WebSocket protocolWebSockets have connection states:
Example:
console.log(socket.readyState);This helps track:
The onopen event triggers when:
Example:
socket.onopen = () => {
console.log("Connected");
};Output:
ConnectedThis confirms:
WebSockets use:
Example:
socket.send("Hello Server");The message is instantly sent to:
This enables:
The onmessage event handles:
Example:
socket.onmessage = (event) => {
console.log(event.data);
};Output example:
Hello ClientServers can send:
Connections can close using:
Example:
socket.close();This terminates:
Example:
socket.onclose = () => {
console.log("Connection Closed");
};Output:
Connection ClosedUseful for:
Example:
socket.onerror = (error) => {
console.log(error);
};This improves:
Example:
const socket = new WebSocket("ws://localhost:3000");
socket.onopen = () => {
socket.send("User Joined");
};
socket.onmessage = (event) => {
console.log(event.data);
};This creates:
Applications commonly exchange:
Example:
socket.send(JSON.stringify({
type: "message",
text: "Hello"
}));Receiving data:
socket.onmessage = (event) => {
const data = JSON.parse(event.data);
console.log(data);
};JSON improves:
Production applications use:
Example:
const socket = new WebSocket("wss://example.com");Benefits:
Node.js commonly uses:
Example server:
const WebSocket = require("ws");
const server = new WebSocket.Server({
port: 3000
});
server.on("connection", socket => {
socket.send("Connected");
});Node.js enables:
| Polling | WebSockets |
|---|---|
| Repeated requests | Persistent connection |
| Higher bandwidth | Lower bandwidth |
| Delayed updates | Instant updates |
Modern real-time systems strongly prefer:
WebSockets are used in:
Modern enterprise applications heavily depend on:
Messages update:
Stock prices stream:
Players exchange:
Flow:
Applications monitor:
Beginners often:
Incorrect example:
socket.send("Hello");Problem:
Correct approach:
socket.onopen = () => {
socket.send("Hello");
};Benefits include:
WebSockets are fundamental in modern real-time development.
Best practices include:
Readable real-time architecture improves maintainability.
Understanding WebSockets in JavaScript helps developers:
WebSockets are essential in advanced modern web development.
WebSockets in JavaScript provide real-time bidirectional communication between client and server using persistent connections. They enable live applications like chats, notifications, games, and dashboards with low latency and efficient communication architecture.
WebSockets are protocols for real-time bidirectional communication.
HTTP uses request-response communication, while WebSockets maintain persistent connections.
It represents WebSocket protocol.
It is the secure encrypted WebSocket protocol.
They are used in chats, live notifications, games, trading apps, and real-time enterprise systems.