Mozilla's getting a new look. What do you think? https://mzl.la/brandsurvey

Firefox 50 for developers

Firefox 50, based on Gecko 50, will ship in November 2016. This article provides information about the changes in this release that will affect developers. Nightly builds of what will become Firefox 50 are currently available on the Beta channel.

Note: Items listed here are tentatively slated for Firefox 50; however, they may be held for a future release if testing shows they're not ready by the time Firefox 50 is due to ship. Please keep an eye on this page to stay up to date on the plans for Firefox 50.

Changes for Web developers

Developer Tools

  • Box model was moved into Computed side panel (bug 1247729).

HTML

CSS

JavaScript

DOM and HTML DOM

IndexedDB

Service Workers

  • The WindowClient.navigate() method has been implemented. This method lets you open a specified URL into a client window which is being controlled by the service worker (bug 1218148).

WebGL

WebRTC

Web Audio API

SVG

  • The allowReorder attribute has been dropped and the behavior it was setting is now the default for SVG <switch> elements (bug 1279690).
  • The defer keyword for the preserveAspectRatio attribute on SVG <image> elements has been removed to follow the latest SVG2 specification (bug 1280425).

Audio/Video

  • The AlignSetting enum (representing possible values for VTTCue.align) incorrectly previously included the value "middle" instead of "center". This has been corrected (bug 1276130).

HTTP

Networking

Miscellaneous

Changes for add-on and Mozilla developers

Tbd.

See also

Older versions

Document Tags and Contributors

 Contributors to this page: wbamberg, Sheppy, fscholz, Sebastianz, teoli, yisibl, chrisdavidmills, arai
 Last updated by: wbamberg,