SOURCE

var app = new Vue({
  el: '#app',
  data: {
    message: 'Hello Vue!'
    // title: '标题'
  }
})

<script src="https://cdn.jsdelivr.net/npm/vue"></script>

<template>
<div id="app">
  {{ message }}
<!--   <span v-bind:title=title>
   sss
  </span> -->
</div>
</template>