I want to increase the height of UIWebView , while user zoom in (like the default mail app in the iPhone ). So, to find the scrollview in the webview and to use UIScrollViewDelegate to add the scrollViewDidZoom zoom scale to add the height of the webview on this method Have tried the code below. // MessageAppDelegate.h @interface MessageAppDelegate: NSObject & LT; UIApplicationDelegate, UIWebViewDelegate, UIScrollViewDelegate & gt; {UIWebView * webview; UIScrollView * scrollview; } //MessageAppDelegate.m - (bool) Application: (UIApplication *) application didFinishLaunchingWithOptions: (NSDictionary *) launchOptions {[self.window makeKeyAndVisible]; Webview = [[UIWebView alloc] initWithFrame: CGRectMake (0, 150, 320, 100)]; Webview.delegate = self; Webview.scalesPageToFit = Yes; Webview.userInteractionEnabled = Yes; [Webview Load HTML String: @ "Meta Name = \" Viewport \ "content = \" width = device-width, initial-scale = 1.0, max-scale = 6.0 use...