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

WebRTC

Others

HTTP

Changes for add-on and Mozilla developers

See also

Older versions

Document Tags and Contributors

 Last updated by: fscholz,