When multiple observers are present, use the bubbling phase if you want closer observers to fire first.

当存在多个观测者时，如果希望首先触发最近的观测者则使用冒泡阶段。

youdao

When multiple observers are present, use the bubbling phase if you want closer observers to fire first.

当存在多个观测者时，如果希望首先触发最近的观测者则使用冒泡阶段。

youdao