diff --git a/web/index.html b/web/index.html
index 0b9d163..0068287 100644
--- a/web/index.html
+++ b/web/index.html
@@ -76,6 +76,13 @@
             <div class="ts horizontal divider">or</div>
             <button id="random" class="ts primary button">隨機配對</button>
         </div>
-    <script src="./menu.js"></script>
+    </div>
+    <!-- Anchor -->
+    <!-- snackbar -->
+    <div class="ts bottom right snackbar">
+        <div class="content"></div>
+        <a class="action"></a>
+    </div>
 </body>
+<script src="./menu.js"></script>
 </html>
\ No newline at end of file
diff --git a/web/menu.js b/web/menu.js
index e3c4f5b..ae93158 100644
--- a/web/menu.js
+++ b/web/menu.js
@@ -45,11 +45,15 @@ firstStep.addEventListener('click',() => { displayCharacter() });
 var roomNum = document.querySelector('#roomNum');
 var roomBtn = document.querySelector('#roomBtn');
 roomBtn.addEventListener('click',() => {
-    if(roomNum.value != null && 0 <= parseInt(roomNum.value) && 99999 >= parseInt(roomNum.value)){
+    var regex = new RegExp('^[0-9]{1,5}$');
+    if(roomNum.value != null && regex.test(roomNum.value)){
         roomID = roomNum.value;
         setter();
         location.href = './cards.html';
     } else {
+        ts('.snackbar').snackbar({
+            content: '請輸入正確的房號!',
+        });
         console.log("room number error");
     }
 });