WebView scrolled event

Dear all community,

I need to know when the user has ended the scroll on a webview displaying a agreement, to display an "Accept" only when the user has read this.

Here is my webview (axml) :

  <WebView x:Name="webView" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
    <WebView.Source>
      <HtmlWebViewSource Html="{Binding Content}" />
    </WebView.Source>
  </WebView>

How can I do that ?..
I'm new on Xamarin, thanks for your help