If a container is not specified, its element's parent is set as the container.

如果没有父容器被指定，默认它的父对象被指定为它的容器。

youdao

If a container is not specified, its element's parent is set as the container.

如果没有父容器被指定，默认它的父对象被指定为它的容器。

youdao