Let suppose you are working on a hybrid application which runs only in single (portrait) mode. One day a requirement come that PDF and Doc Viewer (HTML Page) should support both (landscape, portrait) mode. Your Application loads all the HTML content from the local html files and you need to implement the above functionality only for one HTML file. Let break the above task in the modules: Step 1: Application should detect when the PDF and Doc viewer is open in application. I setup location.href tag in html to " docvieweron:// " and " docvieweroff:// " when page is open and closed respectively. In this way I am getting a delegate callback in web view: WebViewDelegate: - ( BOOL ) webView:( UIWebView *)webView shouldStartLoadWithRequest:( NSURLRequest *)request navigationType: ( UIWebViewNavigationType )navigationType { NSString * urlString = [[request URL ] absoluteString ]; if