Pause / fade iTunes when on YouTube

Hey Verge!

I'm currently looking for a solution on my problem:

i want iTunes to pause the music I'm listening to, when i klick on a YouTube link!

Havent foud anything on the web yet!

Thought of doing something in Automator / Apple Script but I need something that is always running in the background and detecting a " youtube.com/watch[...] "-link and the pauses my music, or sets iTunes volume to 0.

Any ideas how i could do that?

- Maybe an existing app / tool

- or an easy way with Apple Script or Automator?

Thank you all! :)