How can I enable webview background audio play in react native (ios)?

Question

My app plays my content(usually youtube.com video page) with react-native-webview. I want to make the content still played when my app is in background. Now the app just stop playing sound when it became background.

I enabled capability :

This is my react-native-webview code.

<WebView
  allowsFullscreenVideo
  source={{uri: this.state.url}}
  javaScriptEnabled={true}
  mixedContentMode={'always'}
  onShouldStartLoadWithRequest={this._deepLinkGuard}
/>