diff --git a/hello/app.js b/hello/app.js
index 08028bc..62fea48 100644
--- a/hello/app.js
+++ b/hello/app.js
@@ -14,7 +14,9 @@ var app = new Vue({
             { id: 2, text: 'Learn Vue' },
             { id: 3, text: 'Build something awesome' }
         ],
-        label: 'You loaded this page on ' + new Date().toLocaleString()
+        label: 'You loaded this page on ' + new Date().toLocaleString(),
+        isActive: true,
+        hasError: false
     },
     methods: {
         reverseMessage: function () {
diff --git a/hello/index.html b/hello/index.html
index 27922ad..e82a705 100644
--- a/hello/index.html
+++ b/hello/index.html
@@ -28,6 +28,8 @@
             <button v-on:click="reverseMessage">Reverse Message</button>
 
             <input v-model="message"> <span>{{ lenMessage }}</span>
+
+            <p class="static" v-bind:class="{ active: isActive, 'text-danger': hasError }">class</p>
         </div>
         
         <script src="app.js"></script>