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
Developer tools
- In the multi-line mode of the interactive JS interpreter, you can open and save files using the keyboard shortcuts
Ctrl
+O
andCtrl
+S
, respectively (Firefox bug 1592308). - You can set a preference so that asynchronous messages are visually separated (Firefox bug 1592969).
- You can now right/
Ctrl
click 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-scheme
media feature (Firefox bug 1550804).
Removals
- The Scratchpad feature has been removed (Firefox bug 1519103).
HTML
No changes.
CSS
- CSS Shadow Parts are now enabled. This includes the
part
attribute and::part
pseudo-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 —
scale
,rotate
, andtranslate
— are now enabled by default (Firefox bug 1424900).
Removals
SVG
No changes.
JavaScript
- The nullish coalescing operator has been implemented (Firefox bug 1566141).
APIs
New APIs
FormDataEvent
and event-based form participation is now enabled by default (Firefox bug 1594708).- The
crossOriginIsolated
property is now supported (Firefox bug 1591892).
DOM
- The Geolocation API has had some interface name updates, as per recent spec changes (Firefox bug 1575144):
Coordinates
has been changed toGeolocationCoordinates
.Position
has been changed toGeolocationPosition
.PositionError
has been changed toGeolocationPositionError
.
- A number of properties have been updated to use standard stringifiers (Firefox bug 824857):
DOM events
Notification.requestPermission()
andPushManager.subscribe()
can now only be called in response to a user gesture such as aclick
event (Firefox bug 1593644).
Media, Web Audio, and WebRTC
- The
MediaDevices.getDisplayMedia()
method can now only be called in response to a user gesture such as aclick
event (Firefox bug 1580944). - The
RTCRtpContributingSource
dictionary can now include thertpTimestamp
property, which is a source-generated time at which the packet's media was generated or sampled (Firefox bug 1583867).
Removals
- Removed the non-standard
window.mozPaintCount
property. (Firefox bug 1591968) - The
BatteryManager
interface 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
rid=
andpt=
parameters on thesimulcast
attribute. 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).
Security
- Opting-out of MIME sniffing using
X-Content-Type-Options
is now also applied to top-level documents if aContent-type
is provided. This can cause HTML web pages to be downloaded instead of being rendered when they are served with a MIME type other thantext/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
andPublic-Key-Pins-Report-Only
headers are now silently ignored Firefox bug 1412438.
Plugins
No changes.
WebDriver conformance (Marionette)
- Removed
Anon
andAnonAttribute
strategies fromWebDriver:FindElement
andWebDriver:FindElements
commands (Firefox bug 1587627). Webdriver:TakeScreenshot
no longer fails if captured area exceeds upper maximum bound for the canvas width, height, or size (Firefox bug 1590064).
Changes for add-on developers
API changes
- The
browserSettings.ftpProtocolEnabled
property has been implemented (Firefox bug 1592687). - The
BrowserSetting.onChange
event has been implemented (Firefox bug 1410412). - The
captivePortal.canonicalURL
property has been implemented (Firefox bug 1592932). - The callback functions for the
browserAction.onClicked
andpageAction.onClicked
events now include aOnClickData
property 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. - The
browserSettings.tlsVersionRestrictionConfig
property has been implemented and enables the highest and lowest versions of TLS supported by the browser to be read (Firefox bug 1593635).
Manifest changes
No changes.
See also
- Hacks release post: Firefox 72 — our first song of 2020
Older versions
- Firefox 71 for developers
- Firefox 70 for developers
- Firefox 69 for developers
- Firefox 68 for developers
- Firefox 67 for developers
- Firefox 66 for developers
- Firefox 65 for developers
- Firefox 64 for developers
- Firefox 63 for developers
- Firefox 62 for developers
- Firefox 61 for developers
- Firefox 60 for developers
- Firefox 59 for developers
- Firefox 58 for developers
- Firefox 57 for developers
- Firefox 56 for developers
- Firefox 55 for developers
- Firefox 54 for developers
- Firefox 53 for developers
- Firefox 52 for developers
- Firefox 51 for developers
- Firefox 50 for developers
- Firefox 49 for developers
- Firefox 48 for developers
- Firefox 47 for developers
- Firefox 46 for developers
- Firefox 45 for developers
- Firefox 44 for developers
- Firefox 43 for developers
- Firefox 42 for developers
- Firefox 41 for developers