Unless otherwise noted, changes described below apply to the newest Chrome Beta channel release for Android, Chrome OS, Linux, Mac, and Windows.

Push notification improvements
Push notifications allow a site to trigger system-level notifications in the same way that native applications do. The initial version of push notifications relied on service workers to proactively fetch the information for a notification from the server. This led to problems when there were multiple messages in flight or when the device was on a flaky network connection. The latest version of Chrome allows sites to include notification data payloads with their push messages to eliminate the final server check. To protect user privacy, push notification payloads must be encrypted. Push notification payloads are part of the Push API spec and already supported in Firefox.

In addition to payloads, sites can now detect when a notification is closed by the user, enabling better analytics and allowing cross-device notification dismissal. Sites can also control the look of notifications more finely, setting custom timestamps and icons for notification actions. When updating a notification, sites can specify whether the device should alert the user with sound or vibration, or remain silent.

In Chrome 50, notification actions support custom icons.
Declarative preload
Sometimes there are resources needed to fully display a page that Chrome doesn’t know about until other resources are loaded. For example, a large JavaScript file may require a particular stylesheet, but Chrome doesn’t know to load the CSS until the JavaScript has run. Chrome now supports the <link rel='preload'> attribute, allowing developers to specify resources that should be downloaded preemptively and reducing the time to get meaningful content in front of users.
Chrome 50 (left) loading a page with preload vs. Chrome 49 (right) loading the page without.

Other features in this release


Minor changes
  • Chrome now supports the X25519 curve for TLS, allowing faster, simpler encryption.
  • -webkit-background-composite has been removed since it was nonstandard and had low usage.
  • The SVGZoomEvent, which was a no-op in Chrome, has been deprecated to improve spec compliance.
  • The RTCPeerConnection methods createOffer() and createAnswer() have been deprecated to enable promise-based implementations.
  • <link rel='subresource'> has been deprecated in favor of <link rel='preload'>, as described above.
  • XMLHTTPRequestProgressEvent has been removed in favor of ProgressEvent to improve spec compliance.
  • The Document.defaultCharset attribute has been removed to improve spec compliance.
  • KeyboardEvent.prototype.keyLocation has been removed in favor of KeyboardEvent.prototype.location, which is supported across more browsers.
  • The SVGElement.offset* methods have been removed from all elements except HTMLElement to improve spec compliance.

Posted by Peter Beverloo and Nicolás Satragno, Notification Knights