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

To test the latest developer features of Firefox,
install Firefox Developer Edition
Firefox 48 was released on August 2, 2016. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.

Changes for Web developers

Developer Tools

HTML

  • The <details> and <summary> elements have been activated by default on Nightly and Aurora (DevTools), but not on Beta or Release:
  • The meta attributes now also supports the no-referrer-when-downgrade and origin-when-cross-origin values (bug 1178337).

CSS

JavaScript

New APIs

Deprecations and removals

Interfaces/APIs/DOM

DOM & HTML DOM

Canvas 2D

WebGL

No change.

IndexedDB

No change.

Service Workers

No change.

WebRTC

New APIs

No change.

Others

MathML

No change.

SVG

No change.

Audio/Video

No change.

HTTP

  • Support for the upgrade-insecure-requests header, indicating a preference of the client to the server, has been added (bug 1243586).

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

See also

Older versions

Document Tags and Contributors

 Last updated by: Sheppy,