Answer 1

Welcome to SoloLearn
Your question is a bit unclear.
What is the code supposed to do when the button is clicked.
I guess you are talking about the notification API:
https://developer.mozilla.org/en-US/docs/Web/API/Notifications_API/Using_the_Notifications_API
But I'm not sure.
If by notification you meant event:
https://www.sololearn.com/learn/JavaScript/2758

Please clear your question