Edit in JSFiddle

new Vue({
  el: '#app',
  data: {
    message: 'Hello Vue.js!'
  }
});

var app2 = new Vue({
	el:'#app-2',
	data: {
		message: 'You loaded this page on ' + new Date().toLocaleString()
	}
});

var app3 = new Vue({
  el: '#app-3',
  data: {
    seen: false
  }
});

var app4 = new Vue({
  el: '#app-4',
  data: {
    todos: [
      { text: 'Learn JavaScript' },
      { text: 'Learn Vue' },
      { text: 'Build something awesome' }
    ]
  }
});

var app5 = new Vue({
  el: '#app-5',
  data: {
    message: 'Hello Vue.js!'
  },
  methods: {
    reverseMessage: function () {
      this.message = this.message.split('').reverse().join('')
    }
  }
});

var app6 = new Vue({
  el: '#app-6',
  data: {
    message: 'Hello Vue!'
  }
});

Vue.component('todo-item', {
  props: ['todo'],
  template: '<li>{{ todo.text }}</li>'
})
var app7 = new Vue({
  el: '#app-7',
  data: {
    groceryList: [
      { id: 0, text: 'Vegetables' },
      { id: 1, text: 'Cheese' },
      { id: 2, text: 'Whatever else humans are supposed to eat' }
    ]
  }
});
<script src="https://unpkg.com/vue"></script>

<div id="app">
  <p>{{ message }}</p>
</div>
<div id="app-2">
  <span v-bind:title="message">
    Hover your mouse over me for a few seconds
    to see my dynamically bound title!
  </span>
</div>
<div id="app-3">
  <span v-if="seen">Now you see me</span>
</div>
<div id="app-4">
  <ol>
    <li v-for="todo in todos">
      {{ todo.text }}
    </li>
  </ol>
</div>
<div id="app-5">
  <p>{{ message }}</p>
  <button v-on:click="reverseMessage">Reverse Message</button>
</div>
<div id="app-6">
  <p>{{ message }}</p>
  <input v-model="message">
</div>
<div id="app-7">
  <p>Component</p>
  <ol>
    <!--
      Now we provide each todo-item with the todo object
      it's representing, so that its content can be dynamic.
      We also need to provide each component with a "key",
      which will be explained later.
    -->
    <todo-item
      v-for="item in groceryList"
      v-bind:todo="item"
      v-bind:key="item.id">
    </todo-item>
  </ol>
</div>