title: Javascript - Detect is user is subscribed to youtube channel
body: <p>I use Youtube subscribe button (<a href="https://developers.google.com/youtube/youtube_subscribe_button" rel="nofollow">https://developers.google.com/youtube/youtube_subscribe_button</a> ).</p>
  
  <p>Is there any way, while user clicks on it, to initiate my javascript function too?</p>