char counter in mesage box

view/message-board.html

@@ -16,6 +16,7 @@
         <form id="messageForm">
             <input type="text" id="name" placeholder="Your Name" required>
             <textarea id="message" placeholder="Your Message" maxlength="100" required></textarea>
+            <div id="charCount">0 / 100</div>
             <button type="submit">Send</button>
         </form>
         <div id="messages">