diff --git a/en/application-dev/reference/apis/js-apis-stationary.md b/en/application-dev/reference/apis/js-apis-stationary.md
index 7f732445123bce8a0fafde50b26a36548be0eb8e..4e563fc6c366e5296dc9966cfa8ec292f632af1f 100644
--- a/en/application-dev/reference/apis/js-apis-stationary.md
+++ b/en/application-dev/reference/apis/js-apis-stationary.md
@@ -123,7 +123,7 @@ Unsubscribes from the device status.
 | -------------------- | -------------------------------------------------- | ---- | ---------------------------- |
 | activity  | [ActivityType](#activitytype)  | Yes  | Device status type.             |
 | event  | [ActivityEvent](#activityevent)  | Yes  | Event type.             |
-| callback | Callback<[ActivityResponse](#activityresponse)\>  | No  | Callback used to receive reported data. If this parameter is not passed, all callbacks associated with the specified event in the process will be unregistered. |
+| callback | Callback:\<[ActivityResponse](#activityresponse)>  | No  | Callback used to receive reported data, If the callback parameter is not passed or the type passed is undefined, all callbacks associated with the specified event in the process will be unregistered. |
 
 **Example**
 
diff --git a/zh-cn/application-dev/reference/apis/js-apis-stationary.md b/zh-cn/application-dev/reference/apis/js-apis-stationary.md
index b14f185bf3103fc58c2f37cbfa4f434e644c73fc..959445052a71bbcdb09d1622481e24c1eaca4c34 100644
--- a/zh-cn/application-dev/reference/apis/js-apis-stationary.md
+++ b/zh-cn/application-dev/reference/apis/js-apis-stationary.md
@@ -123,7 +123,7 @@ off(activity: ActivityType, event: ActivityEvent, callback?: Callback&lt;Activit
 | -------------------- | -------------------------------------------------- | ---- | ---------------------------- |
 | activity  | [ActivityType](#activitytype)  | 是   | 设备状态能力类型。              |
 | event  | [ActivityEvent](#activityevent)  | 是   | 事件类型。              |
-| callback | Callback<[ActivityResponse](#activityresponse)\>  | 否   | 回调函数，接收上报状态变化事件，如果没有传递callback参数，会移除该进程下订阅该类型得所有callback。  |
+| callback | Callback：\<[ActivityResponse](#activityresponse)>  | 否   | 回调函数，接收上报状态变化事件，如果没有传递callback参数或者传递的类型是undefined，会移除该进程下订阅该类型得所有callback。  |
 
 **示例：**