Ios Wkwebview Not Showing Javascript Alert Dialog

If you encounter the issue of your iOS WKWebView not displaying JavaScript alert dialogs as expected, fear not! This common problem can be quite frustrating but fret not as we'll walk you through some simple steps to resolve it.

First and foremost, let's delve into why this issue might be occurring. The WKWebView component in iOS has certain restrictions when it comes to showing JavaScript alert dialogs. Due to security concerns and the way WKWebView is designed, these dialogs may not behave as they would in a traditional web browser. Therefore, it's essential to implement alternative methods to handle alert dialogs in a WKWebView.

One effective way to work around this limitation is by implementing a custom solution that interacts with JavaScript to display alerts using native iOS components. This approach involves communication between JavaScript running in the WKWebView and native Swift code. By utilizing the WKScriptMessageHandler protocol, you can establish a bridge for passing messages between JavaScript and native code.

Here's a step-by-step guide to resolving the issue:

1. Set up WKWebView Configuration: Configure your WKWebView to support JavaScript interaction by setting up a WKWebViewConfiguration instance and adding a user script message handler.

let webViewConfiguration = WKWebViewConfiguration()
webViewConfiguration.userContentController.add(self, name: "alert")
let webView = WKWebView(frame: .zero, configuration: webViewConfiguration)

2. Implement Message Handler: Implement the message handler in your view controller conforming to the WKScriptMessageHandler protocol. This handler will receive messages from JavaScript alert calls.

extension YourViewController: WKScriptMessageHandler {
    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        if message.name == "alert", let body = message.body as? String {
            // Display a native iOS alert using the message body
            let alertController = UIAlertController(title: "Alert", message: body, preferredStyle: .alert)
            alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
            self.present(alertController, animated: true, completion: nil)
        }
    }
}

3. Inject JavaScript Functionality: Inject JavaScript code into your WKWebView to override the default behavior of alert dialogs and call the native message handler instead.

let script = """
window.alert = function(message) {
    window.webkit.messageHandlers.alert.postMessage(message);
};
"""
webView.evaluateJavaScript(script, completionHandler: nil)

By following these steps, you can ensure that JavaScript alert dialogs are displayed correctly within your WKWebView on iOS. This custom solution provides a seamless user experience while maintaining the security and functionality of WKWebView.

In conclusion, while the default behavior of WKWebView may limit the display of JavaScript alert dialogs, you can overcome this challenge by implementing a custom message handling approach. Happy coding and best of luck in enhancing the user interaction in your iOS applications!