

Under Send Notifications, choose a notification option: Always Ask, Allow, or Block.Click More information in the next panel to bring up the Page Info window.Click the arrow in the Site Information drop-down panel.

You can choose whether or not to give permission for a specific website by following these instructions: If you already gave permission to a site to send notifications, the site will also be able to use the Push API. Sites can also use Push to update data in the background, even without showing you a notification.

Using the Push API, a W3C standard, Firefox receives a push message and can show notifications (if permitted by the user) at any time.
