Firefox 127 for developers
This article provides information about the changes in Firefox 127 that affect developers. Firefox 127 is the current Beta version of Firefox and ships on June 11, 2024.
Changes for web developers
Developer Tools
HTML
Removals
CSS
Removals
JavaScript
- The following
Set
methods are now supported (Firefox bug 1868423):Set.prototype.intersection()
— Returns a new set containing elements in both this set and the given set.Set.prototype.union()
— Returns a new set containing all elements in this set and the given set.Set.prototype.difference()
— Returns a new set containing elements in this set but not in the given set.Set.prototype.symmetricDifference()
— Returns a new set containing elements that are in either this set or the given set, but not in both.Set.prototype.isSubsetOf()
— Returns a boolean indicating if all elements of this set are in the given set.Set.prototype.isSupersetOf()
— Returns a boolean indicating if all elements of the given set are in this set.Set.prototype.isDisjointFrom()
— Returns a boolean indicating if this set has no elements in common with the given set.
Removals
SVG
Removals
HTTP
Removals
Security
Removals
APIs
- The async
Clipboard API
is now fully supported. TheClipboardItem
interface, along with theread()
andwrite()
methods of theClipboard
interface, have been enabled. (Firefox bug 1887845,Firefox bug 1858788).
DOM
Media, WebRTC, and Web Audio
Removals
WebAssembly
Removals
WebDriver conformance (WebDriver BiDi, Marionette)
General
WebDriver BiDi
Marionette
Changes for add-on developers
Removals
Other
Experimental web features
These features are newly shipped in Firefox 127 but are disabled by default. To experiment with them, search for the appropriate preference on the about:config
page and set it to true
. You can find more such features on the Experimental features page.
Older versions
- Firefox 126 for developers
- Firefox 125 for developers
- Firefox 124 for developers
- Firefox 123 for developers
- Firefox 122 for developers
- Firefox 121 for developers
- Firefox 120 for developers
- Firefox 119 for developers
- Firefox 118 for developers
- Firefox 117 for developers
- Firefox 116 for developers
- Firefox 115 for developers
- Firefox 114 for developers
- Firefox 113 for developers
- Firefox 112 for developers
- Firefox 111 for developers
- Firefox 110 for developers
- Firefox 109 for developers
- Firefox 108 for developers
- Firefox 107 for developers
- Firefox 106 for developers
- Firefox 105 for developers
- Firefox 104 for developers
- Firefox 103 for developers
- Firefox 102 for developers
- Firefox 101 for developers
- Firefox 100 for developers
- Firefox 99 for developers
- Firefox 98 for developers
- Firefox 97 for developers
- Firefox 96 for developers