Firefox 140 for developers

Removals

Removals

Removals

Removals

Removals

Removals

• The Cookie Store API is now supported (Firefox bug 1958875).

  This provides a modern, asynchronous Promise-based method of managing cookies, which can be used in both the main thread and in service workers. The API is supported with the exception that cookie objects returned by the get() and getAll() methods of the CookieStore interface, and in the change event, omit all properties other than name and value (matching the information returned by the document.cookie). The other cookie properties can still be set, and these will be used internally.

• Element.innerHTML, Element.outerHTML, Element.getHTML(), ShadowRoot.innerHTML, and ShadowRoot.getHTML() now replace the < and > characters with < and > (respectively) when serializing the HTML to a string. This prevents certain exploits where HTML is serialized and then injected back into the DOM. (Firefox bug 1962084).

DOM

Media, WebRTC, and Web Audio

Removals

Removals

General

WebDriver BiDi

Marionette

• Support added for unspecified in cookies.SameSiteStatus. In addition, unspecified is now the default value for sameSite in cookies.set(). (Firefox bug 1550032)

These features are shipping in Firefox 140 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.

• Notification.maxActions (Nightly): dom.webnotifications.actions.enabled

  The Notification.maxActions read-only static property returns the browser limit on the number of actions that can be associated with a Notification, which you create using ServiceWorkerRegistration.showNotification(). This was released prematurely in Firefox version 138, and this change makes it available only in the Nightly build. (Firefox bug 1963263).

• closedBy attribute for <dialog> (Nightly): dom.dialog.light-dismiss.enabled

  The closedBy attribute of the HTMLDialogElement interface, and corresponding closedby attribute of the <dialog> element, are supported. Developers can use these to specify what mechanisms are able to close the dialogs, such as user interaction outside the dialog ("light dismiss") or programmatic closing. (Firefox bug 1964077).

• Atomics.waitAsync(): javascript.options.atomics_wait_async

  The Atomics.waitAsync() static method waits asynchronously on a shared memory location and returns an object representing the result of the operation. It is non-blocking and usable on the main thread. (Firefox bug 1467846).

• Prioritized Task Scheduling API (Nightly release). The Prioritized Task Scheduling API provides a standardized way to prioritize all tasks belonging to an application, whether they are defined in a website developer's code, or in third-party libraries and frameworks. This adds support for the TaskSignal.any() static method, which returns a signal that is triggered when any of the TaskSignal objects it is created from are triggered. The API is now feature complete. (Firefox bug 1964407).