Change zoom level in a Windows 8 WebView control by injecting JavaScript

Windows8ZoomLevel.cs

zoomLevel.TextChanged += (s, e) =>
{
    Func<WebView, double, bool> zoom = (wv, zoomPercentage) =>
    {
        var script = string.Format(
            "(function () {{ document.styleSheets[0]['rules'][0].style['zoom'] = {0}; }})();", zoomPercentage);

        try
        {
            var result = wv.InvokeScript("eval", new string[] { script });

            return true;
        }
        catch (Exception ex) 
        {
            var notReady = ex.HResult == 0x80020101;

            if (notReady) return false;

            throw;
        }
    };


    double zl;
    if (double.TryParse(zoomLevel.Text, out zl))
    {
        zoom(webView, zl);
    }
};