1# Functions 2 3> **NOTE** 4> 5> - The initial APIs of this module are supported since API version 9. Updates will be marked with a superscript to indicate their earliest API version. 6> 7> - You can preview how this component looks on a real device, but not in DevEco Studio Previewer. 8 9## Module to Import 10 11```ts 12import { webview } from '@kit.ArkWeb'; 13``` 14 15## webview.once 16 17once(type: string, callback: Callback\<void\>): void 18 19Registers a one-time callback for web events of the specified type. Currently, only **webInited** is supported. This callback is triggered when the Web engine initialization is complete. 20 21When the first **Web** component is loaded in an application, the web engine is initialized. When other **Web** components are loaded in the same application, **once()** is not triggered. When the first **Web** component is loaded after the last **Web** component is destroyed in the application, the web engine will be initialized again. 22 23**System capability**: SystemCapability.Web.Webview.Core 24 25**Parameters** 26 27| Name | Type | Mandatory| Description | 28| ------- | ---------------- | ---- | -------------------- | 29| type | string | Yes | Web event type. The value can be **"webInited"**, indicating completion of web initialization. | 30| callback | Callback\<void\> | Yes | Callback to register.| 31 32**Error codes** 33 34For details about the error codes, see [Webview Error Codes](errorcode-webview.md). 35 36| Error Code| Error Message | 37| -------- | ----------------------- | 38| 401 | Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types. 3.Parameter verification failed. | 39 40**Example** 41 42```ts 43// xxx.ets 44import { webview } from '@kit.ArkWeb'; 45 46webview.once("webInited", () => { 47 console.log("configCookieSync"); 48 webview.WebCookieManager.configCookieSync("https://www.example.com", "a=b"); 49}) 50 51@Entry 52@Component 53struct WebComponent { 54 controller: webview.WebviewController = new webview.WebviewController(); 55 56 build() { 57 Column() { 58 Web({ src: 'www.example.com', controller: this.controller }) 59 } 60 } 61} 62``` 63