Untitled

private async Task LoadHTMLContent(ItemViewModel itemVm)
{
    var htmlScript = "<script>function getDocHeight() { " +
                  "return document.getElementById('pageWrapper').offsetHeight; } </script>";

    var htmlConcat = string.Format("<html><head>{0}</head>" +
                                    "<body style="margin:0;padding:0;" " +
                                    ">" +
                                    "<div id="pageWrapper" style="width:100%;" +
                                    "">{1}</div></body></html>", htmlScript, itemVm.Model.Content);


    webView.NavigateToString(htmlConcat);

    string pageContent = await webView.InvokeScriptAsync("getDocHeight",null);
}