diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..6f3a291
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,3 @@
+{
+    "liveServer.settings.port": 5501
+}
\ No newline at end of file
diff --git a/form-validation.js b/form-validation.js
new file mode 100644
index 0000000..eadd90b
--- /dev/null
+++ b/form-validation.js
@@ -0,0 +1,11 @@
+const form = document.getElementById('form');
+function validateForm(event) {
+  const emailInput = document.getElementById('mail');
+  const errorMessage = document.getElementById('error-message');
+  if (emailInput.value !== emailInput.value.toLowerCase()) {
+    event.preventDefault();
+    errorMessage.innerHTML = `Please use only lowercase. try:${emailInput.value.toLowerCase()}`;
+  }
+}
+
+form.addEventListener('submit', validateForm);
\ No newline at end of file
diff --git a/index.html b/index.html
index 17e87b1..f9fd323 100644
--- a/index.html
+++ b/index.html
@@ -164,6 +164,7 @@ <h2 class="white">Contact me</h2>
                             </li>
                         </ul>
                     </li>
+                    <div id="error-message"></div>
                     <li>
                         <div id="maxText" class="input-div">
                         <textarea
@@ -186,6 +187,7 @@ <h2 class="white">Contact me</h2>
         </div>
     </section>
     <script src="scripts.js"></script>
+    <script src="form-validation.js"></script>
     <script src="popup.js"></script>
 </body>
 </html>
\ No newline at end of file