I have a scenario which i want to track form submissions, form is getting loaded within a iframe these form content is loaed from another third-party website.
Page A : We have control header and footer loaded from our side (www.mydomain.com)
Page B(iframe embeded on Page A): loaded within i frame from a third-party website.(www.3rdpartydomain.com)
I wanted to tack form submission and also wants implement data layer to get the values.
I have to implement these via adobe launch.
Please suggest me best practices and way to archive this
The short answer is: You can't.
The long answer is:
There are browser security restrictions that prevent messages and events from being passed between the parent frame and an IFrame, especially when the IFrame loads a page that is not in the same domain as the current web page. This is to prevent all sorts of malicious attacks that I won't get into here.
The only way you can know what is happening in an IFrame that loads a third-party page is if that third-party page posts "messages" back to the parent frame via the postMessage() browser API. But to do so, you need to be able to add code to that third-party page. In your situation, you don't have control of that third-party page, so you're basically out of luck.
Here is a tutorial on how to use postMessage() to communicate between the parent page and the IFrame: https://www.dyn-web.com/tutorials/iframes/postmessage/