notifications

使用底层操作系统提供的通知机制向用户显示通知。由于此 API 使用操作系统的通知机制，因此通知的显示和行为细节可能因操作系统和用户的设置而异。

在 macOS 上，通知的外观大致如下

Example notification on macOS, located below the system clock, with a bold title reading "Click notification" followed by regular text reading "You clicked https://mdn.org.cn/en-US/docs/MDN". The notification has the Firefox Nightly logo on the left side, and a link icon on the right.

在 Windows 上，通知会一直保留在操作中心，直到浏览器关闭。通知的外观大致如下

Example notification on Windows 10, located above the system clock, with a bold title reading "Click notification" followed by regular text reading "You clicked https://mdn.org.cn/en-US/docs/MDN". The notification has a small Firefox logo in the top left corner that is followed by "Mozilla Firefox", and a link icon to the left of the primary notification text.