Can an OS X app interact with the web browser?

Question

I want to make a Mac app that is able to know things about the page the user is currently viewing.

Is this possible? I have 1Password installed, and it seems to be able to fill in forms, so it must be possible. Or am I mistaken in what is happening?

If that is what is happening, how does the Mac app find the current open window, find the forms on that page, and then enter the text into them?

Answer 1

I think 1password has an actual browser plugin, which a user would explicitly give permission to view their visited websites. I would imagine that's how it would be able to prefill forms automatically. If you write a browser plugin, you can do this too, but again by requesting permission from the user first.