alert() not working in WKWebview evaluateJavaScript()

Question

I don\'t why my question is marked as duplicate of this one, first I execute javascript code with evaluateJavaScript as the question title shows which it\'s

Answer 1

First of all you need to implement the required WKUIDelegate methods, in your case you need to implement:

optional func webView(_ webView: WKWebView, 
    runJavaScriptAlertPanelWithMessage message: String, 
         initiatedByFrame frame: WKFrameInfo, 
        completionHandler: @escaping () -> Void)
{
    // parameter **message** will hold your actual alert message.

    // Write Your Customised code to display the alert message
}

Answer 2

There is a working example in this answer. It seems you mightn't have implemented the WKUIDelegate method correctly.

Answer 3

It's my fault here. I've not much experience with WKWebview. I've experience with android's XWalkview, and there execute alert needn't to implement alert with java code. So here I also missed thought I don't need to implementation the alert delegate with swift.

From answer of Onato, I learned how swift execute the alert prompt and confirm, I lost the implementation of these delegate. So I refer to this answer, add below implementation, everything works.

func webView(_ webView: WKWebView, runJavaScriptAlertPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo,
             completionHandler: @escaping () -> Void) {

    let alertController = UIAlertController(title: nil, message: message, preferredStyle: .actionSheet)
    alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: { (action) in
        completionHandler()
    }))

    present(alertController, animated: true, completion: nil)
}


func webView(_ webView: WKWebView, runJavaScriptConfirmPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo,
             completionHandler: @escaping (Bool) -> Void) {

    let alertController = UIAlertController(title: nil, message: message, preferredStyle: .actionSheet)

    alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: { (action) in
        completionHandler(true)
    }))

    alertController.addAction(UIAlertAction(title: "Cancel", style: .default, handler: { (action) in
        completionHandler(false)
    }))

    present(alertController, animated: true, completion: nil)
}


func webView(_ webView: WKWebView, runJavaScriptTextInputPanelWithPrompt prompt: String, defaultText: String?, initiatedByFrame frame: WKFrameInfo,
             completionHandler: @escaping (String?) -> Void) {

    let alertController = UIAlertController(title: nil, message: prompt, preferredStyle: .actionSheet)

    alertController.addTextField { (textField) in
        textField.text = defaultText
    }

    alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: { (action) in
        if let text = alertController.textFields?.first?.text {
            completionHandler(text)
        } else {
            completionHandler(defaultText)
        }
    }))

    alertController.addAction(UIAlertAction(title: "Cancel", style: .default, handler: { (action) in
        completionHandler(nil)
    }))

    present(alertController, animated: true, completion: nil)
}