vuejs清空input file中的值

<span class="upload-btn">
  <img src="./../../common/images/add-img.png" class="u-img">
  <span class="u-tips">添加照片</span>
  <input type="file" ref="feedbakcImg" @change="chooseImg" name="file" id="file">
</span>

清空input file 中的值

that.$refs.feedbakcImg.value =''