Web platform features explorer

📃 November 2015 release notes

Newly available

The following features are newly available:

  • initial: The initial keyword resets any CSS property to its initial value as defined by the specification. For example, the initial value of the display property is inline, regardless of the element being styled. Not to be confused with revert, which resets to the user or browser default style.
  • <template>: The <template> HTML element holds HTML fragments which you can clone and insert into the document using JavaScript.

New in Edge

The following features are now available in Edge:

  • Classes: Classes are an object-oriented syntax for JavaScript prototypes.
  • Encrypted media extensions: The mediaKeys property of HTMLMediaElement and the navigator.requestMediaKeySystemAccess() method control the playback of content subject to digital rights management. Also known as EME.
  • Generators: Generator functions (function*) create iterators that return multiple values, one after another, on-demand.
  • <picture>: The <picture> element is used for art direction in responsive images, where a different image is displayed based on the <source> element.
  • Pointer lock: Provides access to raw mouse movement by locking the target of mouse events to a single element and hiding the mouse cursor.
  • :read-only and :read-write: The :read-only and :read-write CSS pseudo-classes match elements that are read-only or read-write, respectively. For example, :read-only matches <input> and <textarea> elements with the readonly attribute.
  • srcset and sizes: The srcset and sizes attributes for <img> elements set a list of possible sources for the image and a corresponding list of size conditions for choosing a source, to show a responsive image that fits the size of the display.
  • unset: The unset keyword resets any CSS property, removing any values previously set by the author, user, or browser. Inherited properties (like color) reset to the parent element's computed value. Non-inherited properties (like display) reset to the specified initial value (inline).

New in Firefox

The following features are now available in Firefox:

  • Media playback quality: The getVideoPlaybackQuality() method of HTMLVideoElement returns metrics that can be used to determine the playback quality of a video, such as how many frames were dropped.
  • Media source: The MediaSource API is a custom data source for media elements commonly used for adaptive streaming. Also known as Media Source Extensions (MSE).

New in Firefox for Android

The following features are now available in Firefox for Android:

  • Media playback quality: The getVideoPlaybackQuality() method of HTMLVideoElement returns metrics that can be used to determine the playback quality of a video, such as how many frames were dropped.