Xcode & WebView:如果没有internet连接，请加载本地html(回退)

Currently I'm programming an app for iOS using UIWebView. My goal is to display a php site (from my webserver) using a WebView. I'm pretty good with HTMl, CSS, JS and PHP but Object C is not my strength. However I managed to implement everything and my goal is now (when iOS hasn't an internet connection) to display a local file instead of the file on the server after the error alert. After using Google I managed to do it independently, but not as a fallback.Currently I'm programming an app for iOS using