On iOS the tool is Safari 10 's Web Inspector 10 on a Mac (not run here). Turn on Web Inspector in the iPhone's Safari advanced settings, connect it or start the Simulator, enable Show features for web developers in the Mac's Safari settings, and pick the app's page from the Develop menu.
Since iOS 16.4 a WKWebView is not inspectable unless the app sets its inspectable property. cordova-ios 8.1.1's CDVWebViewEngine.m sets it to YES for debug builds and NO for release builds, and reads the same InspectableWebview preference as Android to override either default. If your app does not appear in the Develop menu, you are running a release build.