ws_client.js

let socket = new WebSocket("ws://localhost:1234");
  socket.onopen = function(e) {
  console.log("[open] Connection established");
  console.log("Sending to server");
  socket.send("My name is danx0r");
};

socket.onmessage = function(event) {
  console.log(`[message] Data received from server: ${event.data}`);
  document.getElementById("message").innerHTML = event.data;
};

socket.onclose = function(event) {
  if (event.wasClean) {
    console.log(`[close] Connection closed cleanly, code=${event.code} reason=${event.reason}`);
  } else {
    // e.g. server process killed or network down
    // event.code is usually 1006 in this case
    console.log('[close] Connection died');
  }
};

socket.onerror = function(error) {
  console.log(`[error] ${error.message}`);
};