diff --git a/hello/app.js b/hello/app.js
index 62fea48..b50fed1 100644
--- a/hello/app.js
+++ b/hello/app.js
@@ -16,7 +16,8 @@ var app = new Vue({
         ],
         label: 'You loaded this page on ' + new Date().toLocaleString(),
         isActive: true,
-        hasError: false
+        hasError: false,
+        counter: 0
     },
     methods: {
         reverseMessage: function () {
diff --git a/hello/index.html b/hello/index.html
index e82a705..9214930 100644
--- a/hello/index.html
+++ b/hello/index.html
@@ -30,6 +30,8 @@
             <input v-model="message"> <span>{{ lenMessage }}</span>
 
             <p class="static" v-bind:class="{ active: isActive, 'text-danger': hasError }">class</p>
+
+            <button v-on:click="counter += 1">{{ counter }} clics</button>
         </div>
         
         <script src="app.js"></script>