index.md

title	slug	page-type
Firefox 72 for Developers	Mozilla/Firefox/Releases/72	firefox-release-notes

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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

Console:

• In the multi-line mode of the interactive JS interpreter, you can open and save files using the keyboard shortcuts Ctrl + O and Ctrl + S, respectively (Firefox bug 1592308).
• You can set a preference so that asynchronous messages are visually separated (Firefox bug 1592969).

JavaScript debugger:

• 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).

Network Monitor:

• The Timings tab now shows queued, started, and downloaded times for each resource (Firefox bug 1580431).

Page Inspector:

• 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:

  • {{cssxref("offset")}}
  • {{cssxref("offset-path")}}
  • {{cssxref("offset-anchor")}}
  • {{cssxref("offset-distance")}}
  • {{cssxref("offset-rotate")}}

• The individual transform properties — {{cssxref("scale")}}, {{cssxref("rotate")}}, and {{cssxref("translate")}} — 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

• {{domxref("FormDataEvent")}} and event-based form participation is now enabled by default (Firefox bug 1594708).
• The {{domxref("Window.crossOriginIsolated")}} property and the {{domxref("WorkerGlobalScope.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 to {{domxref("GeolocationCoordinates")}}.
  • Position has been changed to {{domxref("GeolocationPosition")}}.
  • PositionError has been changed to {{domxref("GeolocationPositionError")}}.

• A number of properties have been updated to use standard stringifiers (Firefox bug 824857):

  • {{domxref("DOMTokenList.value")}}
  • {{domxref("HTMLAnchorElement.href")}}
  • {{domxref("Location.href")}}
  • {{domxref("MediaList.mediaText")}}
  • {{domxref("URL.href")}}
  • {{domxref("WorkerLocation.href")}}

DOM events

• {{domxref("Notification.requestPermission_static", "Notification.requestPermission()")}} and {{domxref("PushManager.subscribe()")}} can now only be called in response to a user gesture such as a click event (Firefox bug 1593644).

Media, Web Audio, and WebRTC

• The {{domxref("MediaDevices.getDisplayMedia()")}} method can now only be called in response to a user gesture such as a click event (Firefox bug 1580944).
• The RTCRtpContributingSource dictionary can now include the rtpTimestamp 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 {{domxref("BatteryManager")}} interface is no longer exposed to web content (Firefox bug 1441976).
• {{domxref("Navigator.vibrate()")}} is no longer supported in cross-origin {{htmlelement("iframe")}}s (Firefox bug 1591113).
• WebRTC no longer supports the rid= and pt= parameters on the simulcast 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 {{HTTPHeader("X-Content-Type-Options")}} is now also applied to top-level documents if a {{HTTPHeader("Content-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 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 and Public-Key-Pins-Report-Only headers are now silently ignored Firefox bug 1412438.

Plugins

No changes.

WebDriver conformance (Marionette)

• Removed Anon and AnonAttribute strategies from WebDriver:FindElement and WebDriver: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 and pageAction.onClicked events now include a OnClickData 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 {{WebExtAPIRef("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

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