update zh-cn/application-dev/reference/arkui-js/js-components-common-events.md.

Signed-off-by: NLiAn <lian15@huawei.com>
Signed-off-by: NLiAn <lian15@huawei.com>

zh-cn/application-dev/reference/arkui-js/js-components-common-events.md

 # 通用事件
 
 >  **说明：**
+>
 >  从API version 4开始支持。后续版本如有新增内容，则采用上角标单独标记该内容的起始版本。
 
 ## 事件说明
@@ -241,32 +242,38 @@ setDragImage(pixelmap: PixelMap, offsetX: number,offsetY: number): boolean
 **示例：** 
 
 ```js
-createPixelMap() {
-	let color = new ArrayBuffer(4*96*96);
+import image from '@ohos.multimedia.image';
+
+export default {
+    createPixelMap() {
+        let color = new ArrayBuffer(4 * 96 * 96);
         var buffer = new Uint8Array(color);
         for (var i = 0; i < buffer.length; i++) {
             buffer[i] = (i + 1) % 255;
         }
         let opts = {
-		alphaType:0,
-		editable:true,
-		pixelFormat:4,
-		scaleMode:1,
-		size:{height:96,width:96}
+            alphaType: 0,
+            editable: true,
+            pixelFormat: 4,
+            scaleMode: 1,
+            size: {
+                height: 96, width: 96
             }
-	const promise = image.createPixelMap(color,opts);
-	promise.then((data)=> {
+        }
+        const promise = image.createPixelMap(color, opts);
+        promise.then((data) => {
             console.error('-create pixmap has info message:' + JSON.stringify(data));
             this.pixelMap = data;
             this.pixelMapReader = data;
         })
-},
+    },
 
-onInit() {
+    onInit() {
         this.createPixelMap
-},
+    },
 
-dragStart(e) {
+    dragStart(e) {
         e.dataTransfer.setDragImage(this.pixelMapReader, 50, 50);
+    }
 }
 ```
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