title: @click event is not working in vue.js applicaton
body: <p>I need to change the {{message}} on the click of a button with a alert box. No alert box is showing and the message is also not changing.<br>
  I am new to vue world, the other examples are working but there is a problem with this file only.<br>
  I have used the directive "v-once" on the message tag inside the <code>&lt;h1&gt;</code> tag, the <code>&lt;h2&gt;</code> doesn't have "v-once".<br>
  Please reply me what I have done wrong in the code below.</p>
  
  <pre class="lang-html prettyprint-override"><code> &lt;!DOCTYPE html&gt;
      &lt;html lang="en"&gt;
        &lt;head&gt;
          &lt;meta charset="utf-8"&gt;
          &lt;meta http-equiv="X-UA-Compatible" content="IE=edge"&gt;
          &lt;meta name="viewport" content="width=device-width, initial-scale=1"&gt;
          &lt;title&gt;Vue.js Tutorial | Directives&lt;/title&gt;
  
            &lt;script src="https://unpkg.com/vue@2.0.3/dist/vue.js"&gt;&lt;/script&gt;
          &lt;!-- Bootstrap CSS --&gt;
          &lt;link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous"&gt;
        &lt;/head&gt;
  
        &lt;body&gt;
          &lt;div id="app"&gt;
            &lt;h1 v-once&gt;{{message}}&lt;/h1&gt;
            &lt;h2&gt;{{message}}&lt;/h2&gt;
            &lt;h5 v-show="viewed" v-html="intro"&gt;&lt;/h5&gt;
          &lt;/div&gt;
          &lt;button @click="rewrite" type="button" name="button" &gt;Change&lt;/button&gt;
        &lt;/body&gt;
  
  
  
        &lt;script&gt;
          var app = new Vue({
            el: '#app',
            data: {
              message: 'Hello Vue World',
              intro: 'Welcome to the Tutorial &lt;small&gt;It is all about Vue.js&lt;/small&gt;',
              viewed: true,
            },
            methods: {
              rewrite: function () {
                alert('Button Clicked!'),
                this.message = 'Bye vue World!!!',
              },
            },
          });
        &lt;/script&gt;
  
      &lt;/html&gt;
  </code></pre>