Personalize thank you message in demo

app/javascript/demo.js

@@ -1,9 +1,17 @@
 document.addEventListener('DOMContentLoaded', function() {
   var demoForm = document.getElementById('demo-form');
-  demoForm.addEventListener('tinyforms:submitted', function() {
+  if (!demoForm) {
+    return;
+  }
+
+  demoForm.addEventListener('tinyforms:submitted', function(e) {
+    console.log(e);
+    console.log(e.detail);
+    var name = document.getElementById('demo-submission-name');
     var demoFields = document.getElementById('demo-fields');
     var demoSucess = document.getElementById('demo-success');
     demoFields.style.display = 'none';
     demoSucess.style.display = 'block';
+    name.innerText = e.detail.submission.Name;
   });
 });