WP8.1 WebView problem

(function () {
    "use strict";

    var webView;

    WinJS.UI.Pages.define("/pages/home/home.html", {
        // This function is called whenever a user navigates to this page. It
        // populates the page elements with the app's data.
        ready: function (element, options) {
            // TODO: Initialize the page here.
            webView = document.getElementById("webview");
            webView.navigate("http://www.google.com");

            webView.addEventListener("mswebviewdomcontentloaded", function () {
                var invScr = webView.invokeScriptAsync("eval", "document.getElementById('hplogo').style.backgroundColor = 'black';");
                Debug.write("Debug write");
                invScr.onerror = function () {
                    Debug.write("Doesn't work");
                };
                invScr.oncomplete = function () {
                    Debug.write("Works");
                };
                invScr.start();
            });

        }
    });
})();