Firefox 36 for developers

Changes for Web developers

Developer Tools

Highlights:

• eval sources now appear in the Debugger
• Simpler process for connecting to Firefox for Android
• Box Model Highlighter works on remote targets
• "Invert the call tree" option in the Profiler
• Inspect DOM promises in the console
• Extra "Paste" commands in the Inspector

All devtools bugs fixed between Firefox 35 and Firefox 36.

CSS

• The will-change property has been enabled by default (bug 961871).
• The white-space property is now working on <textarea> HTML elements (bug 82711).
• The unicode-range descriptor is now supported by @font-face (bug 475891), but not enabled by default.
• The properties text-decoration-color, text-decoration-line, and text-decoration-style are unprefixed (bug 825004). The prefixed version are still available for some time to ease transition (bug 1097922).
• The text-decoration property is turned into shorthand property (bug 1039488).
• The properties object-fit and object-position are now supported (bug 624647)
• The contents value of the display property has been experimentally implemented. It is preffed off by default (bug 907396).
• In Quirks mode, the :active and :hover quiver quirk has been altered to be applied less often: it is now used only on links, only if there are no pseudo-element or other pseudo-class in the element and if it isn't part of a pseudo-class element (bug 783213).
• The isolation property has been implemented (bug 1077872).
• CSS <gradient> now applies on the premultiplied colors, matching the spec and other browsers, and getting rid of unexpected gray colors appearing in them (bug 591600).
• Interpolation hint syntax has been added to <gradient> (bug 1074056).
• The scroll-behavior property has been implemented (bug 1010538).

HTML

• Support for <meta name="referrer"> has been added (bug 704320).
• In Firefox, <input> filters specified in the accept attribute will always be selected by default, unless there is a unknown value, that is an unknown mime type or badly formatted value in the accept attribute. Previously specified filters were only selected by default for image/*,video/* and audio/* values (bug 826185).

JavaScript

• The ECMAScript 2015 Symbol data type has been enabled by default (was available in the Nightly channel since version 33) (bug 1066322):
  • Symbol
  • Symbol.for()
  • Symbol.keyFor()
  • Object.getOwnPropertySymbols()
• The old placeholder string "@@iterator" has been replaced with the real ES2015 well-known symbol Symbol.iterator for the iterable interface property key (bug 918828).
• The spec-internal abstract operation ToNumber(string) now supports binary (0b) and octal (0o) literals, this is a potentially breaking change from ES5 (bug 1079120).
  • Number("0b11") now returns 3, not NaN.
  • "0o11" == 9 now returns true, not false.
• The const declaration is now block-scoped and requires an initializer (bug 611388). It also can not be redeclared anymore (bug 1095439).
  • {const a=1}; a; now throws a ReferenceError and does not return 1 anymore due to block-scoping.
  • const a; now throws a SyntaxError ("missing = in const declaration"): An initializer is required.
  • const a = 1; a = 2; now also throws a SyntaxError ("invalid assignment to const a").
• The ES2016 method Array.prototype.includes has been implemented, but for now, it is only enabled in Nightly builds (bug 1069063).
• The delete operator now triggers the "temporal dead zone" when using with let and const (bug 1074571).
• The non-standard let blocks and let expressions are deprecated and will now log a warning in the console. Do not use them anymore, they will be removed in the future.
• WeakMap constructor now handles optional iterable argument (bug 1092537).

Interfaces/APIs/DOM

• The CanvasRenderingContext2D.resetTransform() method of the Canvas API has been implemented (bug 1099148).
• ECDSA is now supported in the Web Crypto API (bug 1034854).
• Our experimental implementation of WebGL 2.0 is going forward!
  • The WebGLQuery interface is available (bug 1048719).
  • The WebGL2RenderingContext.invalidateFrameBuffer() method has been implemented (bug 1076456).
• The MediaDevices interface, containing the Promise-based version of getUserMedia(), has been added. It is available via Navigator.mediaDevices (bug 1033885).
• The EME-related Navigator.requestMediaKeySystemAccess() method, and the related MediaKeySystemAccess, is now supported (bug 1095257).
• The keyschange event is now sent when an EME-related CDM change keys in a session (bug 1081755).
• The default values of the options for MutationObserver.observe() have been updated to match the latest specification (bug 973638).
• Experimental support for virtual reality devices has landed behind the dom.vr.enabled preference, off by default (bug 1036604).
• The function associated with RTCPeerConnection.onsignalingstatechange now receives an event as parameter, as per spec (bug 1075133).
• The experimental implementation of Web Animations make progress: the method AnimationPlayer.play() and AnimationPlayer.pause() are now supported (bug 1070745), as well as AnimationPlayer.playState (bug 1037321).
• The non-standard DOMRequest interface has now a then() method (bug 839838).
• The CSSOM View scroll behavior controlling methods, Element.scroll(), Element.scrollTo(), Element.scrollBy(), and Element.scrollIntoView(), have been implemented or extended (bug 1045754 and bug 1087559).
• Assigning to Element.innerHTML on an SVGElement now create elements in the SVG namespace (bug 886390).
• The nsIWebBrowserPersist.saveURI() method now requires 8 arguments, in an order incompatible with previous releases.
• Support for Media Source Extensions (MSE) is activated by default in non-build releases (Nightly and Developer Edition only) (bug 1000686). It keeps being preffed off on Beta and Release version.

MathML

No change.

SVG

No change.

Audio/Video

No change.

Networking

• Support for SPDY/3 has been removed; support for SPDY/3.1 is still available (bug 1097944).

Security

• RC4 is now considered as insecure and all UI indicators will react as such; SSLv3 has been disabled by default in Firefox 34, but the UI has been changed to help the user better understand what is happening (bug 1093595).
• Also, RC4 is no longer offered in the initial handshake of TLS (bug 1088915).
• The form-action directive of CSP 1.1 is now supported (bug 529697).
• In the preferences of Firefox, The Do not track selection widget is again an on/off switch (bug 1071747).

Changes for add-on and Mozilla developers

Add-on SDK

Highlights

• The sdk/test/httpd module was removed in Firefox 36, please use the addon-httpd npm module instead.
• Add badges to sdk/ui buttons (bug 994280).
• Implemented global require function to access sdk modules anywhere (bug 1070927), using:

var { require } = Cu.import("resource://gre/modules/commonjs/toolkit/require.js", {});

Details

Github commits made between Firefox 35 and Firefox 36.

JavaScript code modules

• PromiseUtils.resolveOrTimeout is implemented (bug 1080466).
• PromiseUtils.defer (a replacement for Promise.defer) is implemented (bug 1093021).

Interfaces

nsIContentPolicy

New constants have been added to nsIContentPolicy to allow Gecko internals and add-on code to better differentiate different types of requests. These are:

TYPE_FETCH

Indicates a content load request initiated by the GlobalFetch.fetch() method.

TYPE_IMAGESET

Indicates a request to load an <img> (with the srcset attribute or <picture> element.

XUL

No change.

Other

• Firefox -remote command line option has been removed (bug 1080319).

See also

• Site Compatibility for Firefox 36

Older versions