You have the option for popups on "agentconnect", that means when an agent answers a call that came from a queue. In fop2.cfg set notify_on_connect and then modify the checkdir.php appropiately to your needs (you can fire a special popup, update a custom div, etc).
If you want to do something on every "link" manager event, you could modify jscallbacks.js and add your code there.
The 1st option requires a little bit of coding, the later one a lot.
Best regards,
