Firefox 136 for developers
This article provides information about the changes in Firefox 136 that affect developers. Firefox 136 is the current Beta version of Firefox and ships on March 4, 2025.
Changes for web developers
Developer Tools
HTML
- The
autocorrect
global attribute allows autocorrection in editable text elements including: most kinds of text<input>
elements,<textarea>
elements, and elements that have thecontenteditable
attribute set. The specific autocorrection behavior depends on the user agent and underlying OS. (Firefox bug 1927977).
Removals
CSS
Removals
JavaScript
Intl.DurationFormat
is now supported, enabling locale-sensitive formatting of durations. (Firefox bug 1933303).
Removals
SVG
Removals
HTTP
- The
Referer
HTTP header is now sent in requests following a page refresh that redirects to a new page (if permitted by theReferrer-Policy
), anddocument.referrer
will be set to the referrer URL after navigating. The page refresh may be triggered by theRefresh
response header, or equivalent<meta>
in markup (for example<meta http-equiv="refresh" content="3;url=https://www.mozilla.org" />
). Note that same-page refreshes are treated as same-page navigation to a page fragment: since the page isn't re-requested,Referer
isn't sent. (Firefox bug 1928291)
Removals
Security
Removals
APIs
-
The maximum size of Data URLs has been increased from 32MB to 512MB, matching the limit for Chromium browsers (Firefox bug 1911300).
-
The Cookie Store API is a modern, asynchronous
Promise
-based method of managing cookies, which can be used in both the main thread and in service workers. A subset of the Cookie Store API has been implemented (Firefox bug 1937477). This includes:- The
CookieStore
interface, for getting, setting, and deleting cookies. - The
Window.cookieStore
andServiceWorkerGlobalScope.cookieStore
properties for gettingCookieStore
instances. - The
change
event (and its interfaceCookieChangeEvent
), which fires in main thread and service worker contexts when cookies are set or deleted.
Note that while any of the supported cookie properties can be set, the cookie objects returned by the
get()
andgetAll()
methods, and in thechange
event, omit all properties other thanname
andvalue
(matching the information returned by thedocument.cookie
). The following interfaces and properties are not implemented:ServiceWorkerRegistration.cookies
,CookieStoreManager
, andExtendableCookieChangeEvent
. - The
DOM
Media, WebRTC, and Web Audio
Removals
WebAssembly
Removals
WebDriver conformance (WebDriver BiDi, Marionette)
General
WebDriver BiDi
Marionette
Changes for add-on developers
menus.update
andmenus.remove
and the aliasescontextMenus.update
andcontextMenus.remove
now reject with an error when the menu item doesn't exist. Previously, the error was ignored and the promise fulfilled. (Firefox bug 1688743).
Removals
Other
Experimental web features
These features are newly shipped in Firefox 136 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.
- Error.captureStackTrace():
javascript.options.experimental.error_capture_stack_trace
. TheError.captureStackTrace()
static method installs stack trace information on a provided object as theError.stack
property. Its main use case is to install a stack trace on a custom error object that does not derive from theError
interface. (Firefox bug 1886820). - Clear-Site-Data: cache:
privacy.clearSiteDataHeader.cache.enabled
. TheClear-Site-Data
header can be used with thecache
or*
directives to clear the browser cache. (Firefox bug 1942272).
Older versions
- Firefox 135 for developers
- Firefox 134 for developers
- Firefox 133 for developers
- Firefox 132 for developers
- Firefox 131 for developers
- Firefox 130 for developers
- Firefox 129 for developers
- Firefox 128 for developers
- Firefox 127 for developers
- 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