Vue

HTML

<div id="app">
  <select v-model="selected">
    <option v-for="data in datas" :value="data">{{data}}</option>
  </select>
  <span>selected item: {{selected}}</span>
</div>

Vue

new Vue({
  el: "#app",
  data: {
    selected : 'item2',
    datas : [
    'item1',
    'item2',
    'item3'
    ]
  }
})