diff --git a/server/static/ui_chat.js b/server/static/ui_chat.js
new file mode 100644
index 0000000..aa2d9c4
--- /dev/null
+++ b/server/static/ui_chat.js
@@ -0,0 +1,36 @@
+export function setupChat(root, socket) {
+  root.innerHTML = `
+    <div class="panel hidden">
+      <div id="chat-log"></div>
+      <div class="row">
+        <input id="chat-input" placeholder="Say something..." />
+        <button id="chat-send">Send</button>
+      </div>
+    </div>
+  `;
+  const panel = root.firstElementChild;
+  const log = panel.querySelector('#chat-log');
+  const input = panel.querySelector('#chat-input');
+
+  function addLine(t) {
+    const div = document.createElement('div');
+    div.textContent = t;
+    log.appendChild(div);
+    log.scrollTop = log.scrollHeight;
+  }
+
+  panel.querySelector('#chat-send').onclick = () => {
+    const t = input.value.trim();
+    if (!t) return;
+    socket.emit('chat:send', { t });
+    input.value = '';
+  };
+
+  input.addEventListener('keydown', e => {
+    if (e.key === 'Enter') panel.querySelector('#chat-send').click();
+  });
+
+  socket.on('chat:push', m => addLine(m));
+
+  window.addChatLine = addLine;
+}