How to track visitors in Yandex.Metrica by the purpose of entering any text on the keyboard on the site?

Question

Marketing

You can say that everything has a goal setting - set a goal for the form submit button and that's it.
But what if I have an embedded third-party form on the site via an iframe and somehow I need to track those who sent the application?
The embedded form cannot be changed and tracked in any way?
But what if in the metric you can somehow make a goal for pressing any keys on the keyboard (typing text)?
Or at least not a goal, but a custom report. The webvisor shows whether the visitor entered the text or not. Is it possible to somehow track the text input by the visitor on the site and filter out only similar visits?
I would be grateful for help.

Answer 1

Goals can be set to any event using js. Including keyup, keydown, etc. - thus registering keystrokes.
Another issue is that an iframe from another domain will not send your site information about what the user did there, based on the security policy. Therefore, it is unlikely that your idea is feasible.