Am using webview_flutter in my flutter app which views a web page comes from the backend of my project. some times I need to use JS to send a message from the web page to my flutter app .. and am using this method for this :

the web page

theCenter.postMessage(myElement.innerHTML); //Sending whatever content as a string

Flutter App

JavascriptChannel(
 name: 'theCenter',
 onMessageReceived:
 (JavascriptMessage message) {
    controller.getNewCenter(message.message);
     }),

The error now comes from the webpage itself as it shows me this error in the console:

Uncaught (in promise) ReferenceError: theCenter is not defined