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Firefox 43 was released on December 15, 2015. 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

Highlights:

All devtools bugs fixed between Firefox 42 and Firefox 43.

CSS

  • Support for the standard, unprefixed version of hyphens has been landed (bug 953408).
  • The shorthand property font has been updated to accept font-stretch values (bug 1057680).
  • To match a latest evolution of the specification, the :fullscreen pseudo-class now selects the whole stack of elements in full screen, and not only the top-level one (bug 1199522).
  • The deprecated SVG values for the writing-mode, lr, lr-tb, rl, tb, and tb-rl, have been added in CSS as aliases to standard properties (bug 1205787).

HTML

  • For <img> with ICO image containing multiple frames, the intrinsic dimension of the image is set to the one of the largest frame, and no more of the smallest frame bug 1201796.
  • The value of the document's viewport (defined with <meta name="viewport>)can now dynamically be changed via JavaScript (bug 976616).

JavaScript

New APIs

Changes regarding the arguments object

Other changes

Interfaces/APIs/DOM

DOM & HTML DOM

No change.

IndexedDB

  • A new feature called locale-aware sorting has been added allowing for the creation of indexes with a locale specified, which can then be used to sort data according to the rules of that locale (bug 871846). This is a non-standard Firefox-specific feature.

Service Workers

WebRTC

Miscellaneous

MathML

No change.

SVG

No change.

Audio/Video

No change.

HTTP

No change.

Networking

No change.

Security

  • Access to Web Storage (i.e. localStorage and sessionStorage) from third-party IFrames is now denied if the user has disabled third-party cookies (bug 536509).
  • This whitelist has even been removed in Nightly and Aurora/Dev Edition of the browser (bug 1201023). It is currently scheduled that this removal will also happen for Beta and Release versions for the next version (Firefox 44).
  • Subresource integrity has been implemented for <script> and <link> that links to stylesheets (bug 992096).

Changes for add-on and Mozilla developers

Interfaces

No change

XUL

No change.

JavaScript code modules

No change.

XPCOM

No change.

Plugins

  • In preparation for future releases to switch over to multi-process content, NPAPI plugins can no longer be run in the same process as the page content. The preferences starting with dom.ipc.plugins are no longer used.

Other

No change.

See also

Older versions

Document Tags and Contributors

Tags: 
 Last updated by: Sebastianz,