Update index.html

index.html

@@ -22,6 +22,17 @@
         <p> Use the <strong>same email</strong> each time to keep your progress on the questions tracked. Thanks again for participating! </p>
         <input type="text" id="email" placeholder="Email"/>
         <br /> <br />
-        <button id="submit"><strong>Let's go!</strong></button>
+        <button id="submit" onclick="launch();"><strong>Let's go!</strong></button>
 	</body>
+    <script>
+      function launch() {
+        var email = document.getElementById("email").value;
+        if (email == "") {
+          // warning message
+          alert("No email provided :(");
+        } else {
+          alert("Email found " + email);
+        }
+      }
+    </script>
 </html>