# Holding a Video Conference with WebRTC The **\** component can start a camera and microphone by calling **navigator.mediaDevices.getUserMedia()**, a standard W3C API, in JavaScript. To call this API, you need to declare the **ohos.permission.CAMERA** and **ohos.permission.MICROPHONE** permissions. The **constraints** parameter in the API is a **MediaStreamConstraints** object that specifies the types of media to request. It contains two members: **video** and **audio**. In the following example, when a user clicks the button for enabling the camera on the frontend page (**index.html**), the **\** component starts the camera and microphone. - Application code: ```ts // xxx.ets import { webview } from '@kit.ArkWeb'; import { abilityAccessCtrl } from '@kit.AbilityKit'; @Entry @Component struct WebComponent { controller: webview.WebviewController = new webview.WebviewController() aboutToAppear() { // Enable web frontend page debugging. webview.WebviewController.setWebDebuggingAccess(true); let atManager = abilityAccessCtrl.createAtManager(); atManager.requestPermissionsFromUser(getContext(this), ['ohos.permission.CAMERA', 'ohos.permission.MICROPHONE']) .then(data => { let result: Array = data.authResults; let hasPermissions1 = true; result.forEach(item => { if (item === -1) { hasPermissions1 = false; } }) if (hasPermissions1) { console.info("hasPermissions1"); } else { console.info(" not hasPermissions1"); } }).catch(() => { return; }); } build() { Column() { Web({ src: $rawfile('index.html'), controller: this.controller }) .onPermissionRequest((event) => { if (event) { AlertDialog.show({ title: 'title', message: 'text', primaryButton: { value: 'deny', action: () => { event.request.deny(); } }, secondaryButton: { value: 'onConfirm', action: () => { event.request.grant(event.request.getAccessibleResource()); } }, cancel: () => { event.request.deny(); } }) } }) } } } ``` - Code of the **index.html** page: ```html

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