JAVASCRIPT

flutter inject javascript in flutter webview

onLoadStop: (controller, url) async {
  var result = await controller.evaluateJavascript(source: "1 + 1");
  print(result.runtimeType); // int
  print(result); // 2
},

flutter webview javascript

onWebViewCreated: (controller) {
  // register a JavaScript handler with name "myHandlerName"
  controller.addJavaScriptHandler(handlerName: 'myHandlerName', callback: (args) {
    // print arguments coming from the JavaScript side!
    print(args);
    // return data to the JavaScript side!
    return {
      'bar': 'bar_value', 'baz': 'baz_value'
    };
  });
},