updated docs against 4490

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

en/application-dev/ability/wantagent.md

 # WantAgent Development
-### Introduction
-The **WantAgent** class encapsulates a **Want** object that specifies a particular action. To trigger a **WantAgent**, you can either call **wantAgent.trigger** to trigger it directly or add it to a notification so that it will be triggered when users tap the notification.
-
-You can use a **WantAgent** in a notification to start an ability or publish a common event.
-
 ### When to Use
-Start another ability through a **WantAgent**.
+The **WantAgent** class encapsulates want information that specifies a particular action, which can be starting an ability or publishing a common event. You can either call **wantAgent.trigger** to trigger a **WantAgent** directly or add a **WantAgent** to a notification so that it will be triggered when users tap the notification. 
 
 ### Available APIs
 | API                                                                                         | Description|
 | ---------------------------------------------------------------------------------------------- | ----------- |
-| wantAgent.getWantAgentInfo(info: WantAgentInfo, callback: AsyncCallback\<WantAgent\>) | Creates a **WantAgent** object. This API uses an asynchronous callback to return the result.|
-| wantAgent.getWantAgent(info: WantAgentInfo): Promise\<WantAgent\>; | Creates a **WantAgent** object. This API uses a promise to return the result.|
-| commonEvent.trigger(agent: WantAgent, triggerInfo: TriggerInfo, callback?: Callback\<CompleteData\>) | Triggers a **WantAgent**.|
+| getWantAgentInfo(info: WantAgentInfo, callback: AsyncCallback\<WantAgent\>) | Creates a **WantAgent** object. This API uses an asynchronous callback to return the result.|
+| getWantAgent(info: WantAgentInfo): Promise\<WantAgent\> | Creates a **WantAgent** object. This API uses a promise to return the result.|
+| trigger(agent: WantAgent, triggerInfo: TriggerInfo, callback?: Callback\<CompleteData\>) | Triggers a **WantAgent** object.|
 
 ### How to Develop
 1. Import the **WantAgent** module.
 
-```javascript
-import wantAgent from '@ohos.wantAgent';
-```
+   ```
+   import wantAgent from '@ohos.wantAgent';
+   ```
    
-2. Create a **WantAgentInfo** object. For details about the data types and parameters of **WantAgentInfo**, see [WantAgent Module](../reference/apis/js-apis-wantAgent.md#wantagentinfo).
+2. Create a **WantAgentInfo** object that will be used for starting an ability. For details about the data types and parameters of **WantAgentInfo**, see [WantAgent](../reference/apis/js-apis-wantAgent.md#wantagentinfo).
 
-```javascript
-private wantAgentObj = null	// Save the WantAgent object created. It will be used to complete the trigger operations.
+   ```
+   private wantAgentObj = null // Save the WantAgent object created. It will be used to complete the trigger operations.
    
-//wantAgentInfo
-var wantAgentInfo = {
+   //wantAgentInfo
+   var wantAgentInfo = {
        wants: [
            {
                deviceId: "",
@@ -39,34 +34,53 @@ var wantAgentInfo = {
                parameters: {}
            }
        ],
-    operationType: OperationType.START_ABILITY,
+       operationType: wantAgent.OperationType.START_ABILITY,
+       requestCode: 0,
+       wantAgentFlags:[wantAgent.WantAgentFlags.CONSTANT_FLAG]
+   }
+   ```
+
+3. Create a **WantAgentInfo** object for publishing a common event.
+
+   ```
+   private wantAgentObj = null // Save the WantAgent object created. It will be used to complete the trigger operations.
+   
+   //wantAgentInfo
+   var wantAgentInfo = {
+       wants: [
+           {
+               action: "event_name", // Set the action name.
+               parameters: {}
+           }
+       ],
+       operationType: wantAgent.OperationType.SEND_COMMON_EVENT,
        requestCode: 0,
-    wantAgentFlags:[WantAgentFlags.CONSTANT_FLAG]
-}
-```
+       wantAgentFlags:[wantAgent.WantAgentFlags.CONSTANT_FLAG]
+   }
+   ```
 
-3. Create a **WantAgent** object and save the returned **wantAgentObj** for subsequent trigger operations.
+4. Create a **WantAgent** object and save the returned **wantAgentObj** for subsequent trigger operations.
 
-```javascript
-// Create a WantAgent object.
-wantAgent.getWantAgent(wantAgentInfo, (err, wantAgentObj) => {
+   ```
+   // Create a WantAgent object.
+   wantAgent.getWantAgent(wantAgentInfo, (err, wantAgentObj) => {
        if (err.code) {
            console.error("[WantAgent]getWantAgent err=" + JSON.stringify(err))
        } else {
            console.log("[WantAgent]getWantAgent success")
            this.wantAgentObj = wantAgentObj
        }
-})
-```
+   })
+   ```
 
-4. Trigger the **WantAgent**.
+5. Trigger the **WantAgent** object.
 
-```
-// Trigger the WantAgent.
-var triggerInfo = {
+   ```
+   // Trigger the WantAgent object.
+   var triggerInfo = {
        code:0
-}
-wantAgent.trigger(wantAgentObj, triggerInfo, (completeData) => {
+   }
+   wantAgent.trigger(wantAgentObj, triggerInfo, (completeData) => {
        console.log("[WantAgent]getWantAgent success, completeData: ",  + JSON.stringify(completeData))
-})
-```
+   })
+   ```