Some tyhigns.

client/public/wsModule.js

@@ -27,14 +27,20 @@ import { renderChat } from "./render.js";
  * @param {HTMLElement} chatEl - The container element for chat entries.
  * @param {HTMLElement} inputContainer - The message input area element.
  * @param {HTMLElement} usersListEl - The element displaying the online users.
+ * @param {string} wsDomain - Host (and optional port) for the WebSocket server.
  * @returns {{ socket: WebSocket, sendMessage: (content: string) => void }}
  */
-export function initWebSocket(username, chatEl, inputContainer, usersListEl) {
-  const socket = new WebSocket( //"ws://localhost:8080");
-    (location.protocol === "https:" ? "wss" : "ws") +
-      "://" +
-      location.host +
-      "/ws",
+export function initWebSocket(
+  username,
+  chatEl,
+  inputContainer,
+  usersListEl,
+  wsDomain,
+) {
+  const socket = new WebSocket(
+    `${location.protocol === "https:" ? "wss" : "ws"}://${
+      wsDomain || location.host
+    }/ws`,
     "coms",
   );