Can I somehow check if the stageWebView didn't load the webpage? For example if the user doesn't have internet connection, it won't load google.com... Can I then check if it failed loading Google.com?
Yes! StageWebView
throws an ErrorEvent.ERROR
so you can just set up a listener for it:
webView.addEventListener(ErrorEvent.ERROR, onError); //webView is a StageWebView
function onError(e:ErrorEvent):void
{
trace("Page is not available. Try reloading.");
}