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Firefox 92 for developers - Mozilla | MDN
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Firefox 92 for developers
This article provides information about the changes in Firefox 92 that will affect developers. Firefox 92 was released on September 7, 2021.
Note: See also Time for a review of Firefox 92 on Mozilla Hacks.
Changes for web developers
HTML
No changes
CSS
- The keywords
avoid-pageandavoid-columnare now supported for thebreak-insideproperty (Firefox bug 1722945). - The two-value syntax for the
font-size-adjustproperty is now supported (Firefox bug 1720131). - The
size-adjustdescriptor is now supported (Firefox bug 1720131). - The CSS
accent-colorproperty has been implemented (Firefox bug 1722031). - The
system-uivalue is now supported for thefont-familyproperty (Firefox bug 1226042).
JavaScript
Object.hasOwn()can be used to test whether a property was defined on an object or inherited (Firefox bug 1721149).- The default 5MB storage quota is now available to each origin. The quota previously applied to an entire domain group (also known as eTLD+1 domain; e.g.,
*.wikipedia.org). (Firefox bug 1064466). - Storage quotas for
Window.localStorageare now shared with IndexedDB API andCache(Firefox bug 742822).
HTTP
- Firefox will automatically upgrade an HTTP request to HTTPS when a usable HTTPS RR is available.
It will also use information provided in an HTTPS RR to optimize the process of establishing HTTPS connections—this is conceptually similar to using the
Alt-Svcheader. (Firefox bug 1721132).
APIs
- The
disabledFeaturesstatic property has been implemented for Custom Elements (Firefox bug 1723396).
DOM
- The Imperative Slotting API (part of the Shadow DOM API) Has been implemented. (Firefox bug 1705141)
- You can now monitor for changes to text selections in
<input>or<textarea>by listening forselectionchangeevents inHTMLInputElementandHTMLTextAreaElement, respectively (Firefox bug 1648944).
Media, WebRTC, and Web Audio
- Access to audio output devices, like speakers and headphones, is now protected by the speaker-selection feature policy (Firefox bug 1577199).
WebDriver conformance (Marionette)
- Improved support for the
webSocketUrlcapability, which now returns the WebDriver BiDi websocket URL iftruewas passed and if BiDi is supported. (Firefox bug 1692984).
Changes for add-on developers
- Support for
cookieStoreIdis added todownloads.download,downloads.DownloadQuery, anddownloads.DownloadItem. The addition to the typesdownloads.DownloadQueryanddownloads.DownloadItemprovides support indownloads.searchanddownloads.erase. Web extensions can now associate downloads with specific cookie stores, such as container tabs (contextual identities). (Firefox bug 1669566)