<select v-model="selected">
 <option disabled value="">请选择</option>
 <option>A</option>
 <option>B</option>
 <option>C</option>
 </select>
 <span>Selected: {{ selected }}</span>
data: {
 selected: ''
 }

<select v-model="selected" multiple style="width: 50px;">
 <option>A</option>
 <option>B</option>
 <option>C</option>
 </select>
 <br>
 <span>Selected: {{ selected }}</span>

data: {
 selected: []
 }

<select v-model="selected">
 <option v-for="option in options" v-bind:value="option.value">
 {{ option.text }}
 </option>
</select>
<span>Selected: {{ selected }}</span>

new Vue({
 el: '...',
 data: {
 selected: 'A',
 options: [
  { text: 'One', value: 'A' },
  { text: 'Two', value: 'B' },
  { text: 'Three', value: 'C' }
 ]
 }
})

<select v-model="selected">
 <!-- 内联对象字面量 -->
 <option v-bind:value="{ number: 123 }">123</option>
</select>

// 当选中时
typeof vm.selected // => 'object'
vm.selected.number // => 123