Please note, this is a STATIC archive of website developer.mozilla.org from 03 Nov 2016, cach3.com does not collect or store any user information, there is no "phishing" involved.

Firefox 51 for developers

Firefox 51, based on Gecko 51, will ship in January 2017. This article provides information about the changes in this release that will affect developers. Nightly builds of what will become Firefox 51 are currently available on the Developer Edition channel. Some experimental features whose release dates are uncertain or undecided are discussed on the page Experimental features in Firefox. Some features described there may be available in Firefox 51.

Items listed here are tentatively slated for Firefox 51; however, they may be held for a future release if testing shows they're not ready by the time Firefox 51 is due to ship. Please keep an eye on this page to stay up to date on the plans for Firefox 51.

Changes for Web developers

Developer Tools

No change.

HTML

No change.

CSS

JavaScript

Interfaces/APIs/DOM

DOM & HTML DOM

  • Throttling in background tabs of timers created by Window.setInterval() and Window.setTimeout() was changed in Firefox 50 to no longer occur if a Web Audio API AudioContext is actively playing sound. However, this didn't resolve all scenarios in which timing-sensitive audio playback (such as music players generating individual notes using timers) could fail to work properly. For that reason, Firefox 51 no longer throttles background tabs which have an AudioContext, even if it's not currently playing sound.
  • The DOMImplementation.hasFeature() now returns true in all cases (bug 984778).

Canvas

WebGL

No change.

IndexedDB

No change.

Service Workers

No change.

WebRTC

New APIs

No change.

Others

MathML

No change.

SVG

Audio/Video

  • Add FLAC support (FLAC codec) in both FLAC and Ogg containers (bug 1195723). Supported FLAC mimetype: audio/flac, audio/x-flac. For FLAC in Ogg: audio/ogg; codecs=flac and video/ogg; codecs=flac

HTTP

No change.

Networking

No change.

Security

No change.

Changes for add-on and Mozilla developers

Interfaces

No change.

XUL

No change.

JavaScript code modules

No change.

XPCOM

No change.

Other

  • The Mozilla-specific Social API has been substantially changed (largely to remove APIs no longer used), as follows:
    • The MozSocial interface and the navigator.mozSocial property which supports it have been removed.
    • The Social Bookmarks API has been removed.
    • The Social chat functionality has been removed.
    • The Social Status API has been removed.
    • All of the social widgets, except for the Share panel, have been removed. This includes the social sidebar, flyover panels, and so forth.
    • All supporting user interface features and functionality for the removed APIs have been removed as well.
    • Social service provider manifest properties supporting the removed functionality are no longer supported.

See also

Older versions

Document Tags and Contributors

 Contributors to this page: Sheppy, teoli, fscholz, yisibl, isonic, Sebastianz, evilpie, jyavenard
 Last updated by: Sheppy,