window.parent.postMessage not working for android app

[Devanand]

I have a HTML e-learning course installed on clients app.

So client can launch the HTML course and navigate through the course.

Our HTML course have some messages to communicate with app.
In javascript I have written like this,

var msg = {
messageId: GetMessageId(),
timestamp: GetTimeStamp(),
};
window.parent.postMessage(msg, '*');

But the code is not working for android mobile app, while its working on chrome or any other browsers.

Please let me know about the solution as I am not a android developer.