AddJSToWebView.swift

 private func addPageHasChangedDelegateScript(wkWebController: WKUserContentController) {
        // load the script from the file and create a WKUserScript object
        let scriptURL = Bundle.main.path(forResource: Constants.detectPageChangeScript, ofType: "js")
        let scriptContent = try! String.init(contentsOfFile: scriptURL!)
        let script = WKUserScript(source: scriptContent, injectionTime: .atDocumentStart, forMainFrameOnly: false)

	// Add the script to the WKUserContentController 
        wkWebController.addUserScript(script)

	// Register for receiving callbacks from javascript for a notification name 
        wkWebController.add(self, name: ”notification_name”)
 }