updated docs against 4586

Signed-off-by: Nwusongqing <wusongqing@huawei.com>

en/application-dev/reference/apis/js-apis-application-applicationContext.md

 # ApplicationContext
 
-> **NOTE**<br>
+> **NOTE**
+> 
 > The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version. 
-
+> The APIs of this module can be used only in the stage model.
 
 Provides application-level context and APIs for registering and deregistering the ability lifecycle listener in an application.
 
@@ -41,14 +42,6 @@ Registers a listener to monitor the ability lifecycle of the application.
 | ------ | ------------------------------ |
 | number | ID of the registered listener. The ID is incremented by 1 each time the listener is registered. When the ID exceeds 2^63-1, **-1** is returned.|
 
-**Example**
-
-  ```js
-  let applicationContext = this.context.getApplicationContext();
-  console.log("stage applicationContext: " + JSON.stringify(applicationContext));
-  let lifecycleid = applicationContext.registerAbilityLifecycleCallback(AbilityLifecycleCallback);
-  console.log("registerAbilityLifecycleCallback number: " + JSON.stringify(lifecycleid));
-  ```
 
 ## ApplicationContext.unregisterAbilityLifecycleCallback
 
@@ -68,9 +61,47 @@ Deregisters the listener that monitors the ability lifecycle of the application.
 **Example**
 
   ```js
+  import AbilityStage from "@ohos.application.AbilityStage";
+
+  var lifecycleid;
+
+  export default class MyAbilityStage extends AbilityStage {
+      onCreate() {
+          console.log("MyAbilityStage onCreate")
+          let AbilityLifecycleCallback  =  {
+              onAbilityCreate(ability){
+                  console.log("AbilityLifecycleCallback onAbilityCreate ability:" + JSON.stringify(ability));        
+              },
+              onAbilityWindowStageCreate(ability){
+                  console.log("AbilityLifecycleCallback onAbilityWindowStageCreate ability:" + JSON.stringify(ability));           
+              },
+              onAbilityWindowStageDestroy(ability){
+                  console.log("AbilityLifecycleCallback onAbilityWindowStageDestroy ability:" + JSON.stringify(ability));
+              },
+              onAbilityDestroy(ability){
+                  console.log("AbilityLifecycleCallback onAbilityDestroy ability:" + JSON.stringify(ability));             
+              },
+              onAbilityForeground(ability){
+                  console.log("AbilityLifecycleCallback onAbilityForeground ability:" + JSON.stringify(ability));             
+              },
+              onAbilityBackground(ability){
+                  console.log("AbilityLifecycleCallback onAbilityBackground ability:" + JSON.stringify(ability));              
+              },
+              onAbilityContinue(ability){
+                  console.log("AbilityLifecycleCallback onAbilityContinue ability:" + JSON.stringify(ability));
+              }
+          }
+          // 1. Obtain applicationContext through the context attribute.
+          let applicationContext = this.context.getApplicationContext();
+          // 2. Use applicationContext to register a listener for the ability lifecycle in the application.
+          lifecycleid = applicationContext.registerAbilityLifecycleCallback(AbilityLifecycleCallback);
+          console.log("registerAbilityLifecycleCallback number: " + JSON.stringify(lifecycleid));       
+      }
+      onDestroy() {
           let applicationContext = this.context.getApplicationContext();
-  console.log("stage applicationContext: " + JSON.stringify(applicationContext));
           applicationContext.unregisterAbilityLifecycleCallback(lifecycleid, (error, data) => {
           console.log("unregisterAbilityLifecycleCallback success, err: " + JSON.stringify(error));
           });
+      }
+  }
   ```