i am working with uwp webview i have read a html file from my local with ms-appdata:///local/Index.html while reading the html file it will retun a value but i don't know how to read it

Question

what i have tried is

the webview is working well but the data which is return will be in the format i need to read the data to store in local

Uri fileUri = new Uri("ms-appdata:///local/Index.html");
                web.Navigate(fileUri);

private async void Web_NavigationStarting(WebView sender, WebViewNavigationStartingEventArgs args)
        {
            string functionString = "window.onerror = function(error, url, line) {window.external.notify( 'ERR:'+error+' url'+url+' Line: '+line);};";
            var ret = await web.InvokeScriptAsync("eval", new string[] { functionString });
         
        }

<WebView x:Name="web"/>