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-page
andavoid-column
are now supported for thebreak-inside
property (bug 1722945). - The two-value syntax for the
font-size-adjust
property is now supported (bug 1720131). - The
@font-face/size-adjust
descriptor is now supported (bug 1720131). - The CSS
accent-color
property has been implemented (bug 1722031). - The
system-ui
value is now supported for thefont-family
property (bug 1226042).
JavaScript
Object.hasOwn()
can be used to test whether a property was defined on an object or inherited (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
). (bug 1064466). - Storage quotas for
Window.localStorage
are now shared with IndexedDB API andCache API
(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 connectionsâ âthis is conceptually similar to using the
Alt-Svc
header. (bug 1721132).
APIs
- The
disabledFeatures
static property has been implemented for Custom Elements (bug 1723396).
DOM
- The Imperative Slotting API (part of the Shadow Dom API) Has been implemented. (bug 1705141)
- You can now monitor for changes to text selections in
<input>
or<textarea>
by listening forselectionchange
events inHTMLInputElement
andHTMLTextAreaElement
, respectively (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 (bug 1577199).
WebDriver conformance (Marionette)
- Improved support for the
webSocketUrl
capability, which now returns the WebDriver BiDi websocket URL iftrue
was passed and if BiDi is supported. (bug 1692984).
Changes for add-on developers
- Support for
cookieStoreId
is added todownloads.download
,downloads.DownloadQuery
, anddownloads.DownloadItem
. The addition to the typesdownloads.DownloadQuery
anddownloads.DownloadItem
provides support indownloads.search
anddownloads.erase
. Web extensions can now associate downloads with specific cookie stores, such as container tabs (contextual identities). (bug 1669566)
Older versions
- Firefox 91 for developers
- Firefox 90 for developers
- Firefox 89 for developers
- Firefox 88 for developers
- Firefox 87 for developers
- Firefox 86 for developers
- Firefox 85 for developers
- Firefox 84 for developers
- Firefox 83 for developers
- Firefox 82 for developers
- Firefox 81 for developers
- Firefox 80 for developers
- Firefox 79 for developers
- Firefox 78 for developers
- Firefox 77 for developers
- Firefox 76 for developers
- Firefox 75 for developers
- Firefox 74 for developers
- Firefox 73 for developers
- Firefox 72 for developers
- 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