dependencies:
  flutter_jsbridge_jk: ^0.0.6

...
final JsBridge _jsBridge = JsBridge();
...
WebView(
    initialUrl: "http://www.adger.me",
    javascriptMode: JavascriptMode.unrestricted,
    onWebViewCreated: (WebViewController webViewController) async {
        _jsBridge.loadJs(webViewController);
        _controller.complete(webViewController);
        _jsBridge.registerHandler("getToken", onCallBack: (data, func) {
            // return token to js
            func({"token": "token"});
        });
        _jsBridge.registerHandler("IAPpayment", onCallBack: (data, func) {
            print("js call flutter iap");
        });
        _jsBridge.registerHandler("back", onCallBack: (data, func) {
            print("js call flutter back");
        });
    },
    navigationDelegate: (NavigationRequest request) {
        if (_jsBridge.handlerUrl(request.url)) {
            return NavigationDecision.navigate;
        }
        return NavigationDecision.prevent;
    },
    onPageStarted: (url) {
        _jsBridge.init();
    },
))