How to Turn Off Website Notifications in Safari
In OS X Mavericks and above, you can subscribe to websites' push notifications, which will show you things like breaking news or new content you might be interested in at the top-right corner of your screen. Although this can be a helpful feature, you might want to have better control over these possibly-distracting notifications.
Sites that support push notifications usually ask you when you visit them if you'd like to allow those alerts. Some sites let you customize the kinds of notifications you get, such as all new articles or just the most important ones. Whatever you decide at the time, you can later prevent or allow notifications from websites in Safari's settings.
1. Click Preferences from the Safari menu.
2. Go to the Notifications tab.
3. Click Allow or Deny next to the website you want to edit.
4. Select a site and click the Remove button if you want to delete it from the list completely .
You could also click the Remove All button to remove all of the sites from the list. When you visit these sites, you'll be asked again to allow push notifications--unless you uncheck the box that says "Allow websites to ask for permission to send push notifications."
5. Click the Notifications Preferences button to further customize sites' push notifications in OS X's System Preferences. Here you adjust the alert style, lock screen notifications, and number of alerts shown in Notification Center.