Firefox 72 for Developers
This article provides information about the changes in Firefox 72 that will affect developers. Firefox 72 was released on January 7, 2020.
Changes for web developers
- In the multi-line mode of the interactive JS interpreter, you can open and save files using the keyboard shortcuts
S, respectively (Firefox bug 1592308).
- You can set a preference so that asynchronous messages are visually separated (Firefox bug 1592969).
- You can now right/
Ctrlclick on objects in the Scopes panel, and choose Property set or Property get to set watchpoints (Firefox bug 1574192).
- The Timings tab now shows queued, started, and downloaded times for each resource (Firefox bug 1580431).
- You can set a preference to enable a simulator for different values of the
prefers-color-schememedia feature (Firefox bug 1550804).
- The Scratchpad feature has been removed (Firefox bug 1519103).
- CSS Shadow Parts are now enabled. This includes the
::partpseudo-element, which allow shadow hosts to selectively expose chosen elements from their shadow tree to the outside page for styling purposes (Firefox bug 1559074).
- CSS Motion Path has been shipped (Firefox bug 1582554, also see the Intent to Ship). This includes:
- The individual transform properties —
translate— are now enabled by default (Firefox bug 1424900).
- The nullish coalescing operator has been implemented (Firefox bug 1566141).
FormDataEventand event-based form participation is now enabled by default (Firefox bug 1594708).
crossOriginIsolatedproperty is now supported (Firefox bug 1591892).
- The Geolocation API has had some interface name updates, as per recent spec changes (Firefox bug 1575144):
Coordinateshas been changed to
Positionhas been changed to
PositionErrorhas been changed to
- A number of properties have been updated to use standard stringifiers (Firefox bug 824857):
PushManager.subscribe()can now only be called in response to a user gesture such as a
clickevent (Firefox bug 1593644).
Media, Web Audio, and WebRTC
MediaDevices.getDisplayMedia()method can now only be called in response to a user gesture such as a
clickevent (Firefox bug 1580944).
RTCRtpContributingSourcedictionary can now include the
rtpTimestampproperty, which is a source-generated time at which the packet's media was generated or sampled (Firefox bug 1583867).
- Removed the non-standard
window.mozPaintCountproperty. (Firefox bug 1591968)
BatteryManagerinterface is no longer exposed to web content (Firefox bug 1441976).
Navigator.vibrate()is no longer supported in cross-origin
<iframe>s (Firefox bug 1591113).
- WebRTC no longer supports the
pt=parameters on the
simulcastattribute. The new syntax for a line such as "
a=simulcast: send rid=7 recv rid=8" is now "
a=simulcast: send 7 recv 8". The new syntax has been supported since Firefox 68, so now it's time tor retire support for the old syntax (Firefox bug 1470568).
- Opting-out of MIME sniffing using
X-Content-Type-Optionsis now also applied to top-level documents if a
Content-typeis provided. This can cause HTML web pages to be downloaded instead of being rendered when they are served with a MIME type other than
text/html. Make sure to set both headers correctly. (Firefox bug 1591932).
- Dropped the support for HTTP Public Key Pinning (HPKP) because of the low adoption rate and interoperability risk. The
Public-Key-Pins-Report-Onlyheaders are now silently ignored Firefox bug 1412438.
WebDriver conformance (Marionette)
WebDriver:FindElementscommands (Firefox bug 1587627).
Webdriver:TakeScreenshotno longer fails if captured area exceeds upper maximum bound for the canvas width, height, or size (Firefox bug 1590064).
Changes for add-on developers
browserSettings.ftpProtocolEnabledproperty has been implemented (Firefox bug 1592687).
BrowserSetting.onChangeevent has been implemented (Firefox bug 1410412).
captivePortal.canonicalURLproperty has been implemented (Firefox bug 1592932).
- The callback functions for the
pageAction.onClickedevents now include a
OnClickDataproperty containing an object whose properties describe the mouse button pressed along with any keyboard modifiers (Firefox bug 1405031). This allows support for additional types of mouse click.
browserSettings.tlsVersionRestrictionConfigproperty has been implemented and enables the highest and lowest versions of TLS supported by the browser to be read (Firefox bug 1593635).
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