vue select 多选功能

<el-form-item label="标签" prop="tapid" >
    <el-select v-model="tapid" multiple  placeholder="请选择"   >
        <el-option
                v-for="item in tap_options"
                :key="item.value"
                :label="item.label"
                :value="item.value">
        </el-option>
    </el-select>
</el-form-item>

data () {

tap_options: [{
    value: '',
    label: '全部'
}
],

tapid:[],
}