Can you explain what web sockets are and how they work in the context of web development?

WebSockets are a protocol that provides a two-way persistent connection between a client (e.g., a browser) and a server. Unlike traditional HTTP, where the client sends a request and receives a response, WebSockets allow the server to send data to the client at any time without repeated requests.

Here's how they work:

1. The client initiates a connection via HTTP with the header Upgrade: websocket.
2. If the server supports WebSockets, the connection is 'upgraded' from HTTP to WebSocket.
3. After establishing the connection, the client and server can exchange messages in real time.

An example use case is chat, online games, or updating data on a page without reloading.

Here's an example in JavaScript for connecting to a WebSocket:

const socket = new WebSocket('wss://example.com/socket');
socket.onopen = () => {
  console.log('Connection established');
  socket.send('Hello server!');
};
socket.onmessage = event => {
  console.log('Received message:', event.data);
};