add WKWebView event handler

@@ -9,7 +9,7 @@ import Foundation
 import UIKit
 import WebKit
 
-@objc public class CampaignViewController: UIViewController, WKNavigationDelegate {
+@objc public class CampaignViewController: UIViewController, WKNavigationDelegate, WKScriptMessageHandler {
     @IBOutlet weak var webview: WKWebView!
     
     public var campaignUrl: String = ""
@@ -23,6 +23,14 @@ import WebKit
         let url = URL(string: campaignUrl)!
         webview.load(URLRequest(url: url))
         webview.allowsBackForwardNavigationGestures = true
+
+        webview.configuration.userContentController.add(self, name: "Cosmote")
+    }
+
+    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
+        print("=== event callback ===")
+        print(message.name, message.body)
+        print("=== event callback ===")
     }
 
 }