element-ui Upload 上传获取当前选择的视频时长

          <el-upload
              class="upload-demo"
              ref="vidos"
              :action="URL+'/api/post/file'"
              :data="date"
              :on-success="handleAvatarAUDIO"
              :before-upload="beforeAvatarAUDIO" //将用到此方法
              :on-progress="beforeAvatarUpload"
              accept=".mp4"
              :auto-upload="vidoauto"
              :on-change="AvatarAUDIO"
              :file-list="fileList"
            >

beforeAvatarAUDIO(file){
　　let url = URL.createObjectURL(file)
    var audioElement = new Audio(url)
    audioElement.addEventListener('loadedmetadata',function(){
　　　　let playTime = audioElement.duration; //playTime就是当前视频长度
   })

}