讓按鈕強制失焦，變回點選之前的樣式

@click="handlePreview($event,scope.row)"


handlePreview(event, row) {

  this.drawerImg = row;
  this.drawerVisible = true;

  let target = event.target;
  if (target.nodeName === "BUTTON" || target.nodeName === "SPAN") {
    target.parentNode.blur();
  }
  target.blur();
}