The latest version of Mozilla's Firefox browser has a trick up its sleeve that could save you time and battery: push notifications. This means, with your permission, that websites can send messages that appear directly on your desktop — even if you don't have that site open. This lets you close unnecessary tabs, saving you processing power and battery life, and could be especially useful for the likes of Facebook, Twitter, and Gmail, where you want to keep an eye on incoming messages. Mozilla says that as with geolocation and webcams, users will specifically have to grant access to websites that want to send them notifications, and can revoke them at any time.

A push notification on Firefox. A website asking permission to send push notifications.

Push notifications are already available for Chrome and Safari, although using different technology. Both Firefox and Chrome are using the "web push" protocol and associated API developed by the W3C (Worldwide Web Consortium), while Apple uses its own Safari Push Notifications standard on OS X Mavericks. Microsoft, meanwhile, says that adding support for web push to its Edge browser is currently "under consideration," although it doesn't look like it'll ever be available on Internet Explorer. Well, you wouldn't want notifications from beyond the grave.