Firefox 94 release notes for developers

This article provides information about the changes in Firefox 94 that will affect developers. Firefox 94 was released on November 2nd, 2021

Changes for web developers

HTML

No notable changes

CSS

No notable changes

JavaScript

No notable changes

APIs

• The {{DOMxRef("Window.structuredClone()")}} and {{DOMxRef("WorkerGlobalScope.structuredClone()")}} function is now supported for copying complex JavaScript objects (Firefox bug 1722576).

DOM

• Developers can now provide a hint for the enter key label/icon used on virtual keyboards, using either HTMLElement.enterkeyhint or the global attribute enterkeyhint (Firefox bug 1648332).
• The {{domxref("HTMLScriptElement.supports_static", "HTMLScriptElement.supports()")}} static method is now supported. This provides a simple and unified method for feature checking whether a browser supports particular types of scripts, such as JavaScript modules or classic scripts (Firefox bug 1729239).
• The {{domxref("ShadowRoot.delegatesFocus")}} property is now supported, allowing code to check whether the delegatesFocus property was set when the shadow DOM was attached (Firefox bug 1413836).

WebDriver conformance (Marionette)

• WebDriver:GetWindowHandle and WebDriver:GetWindowHandles now return handles for browser windows instead of tabs, when chrome scope is enabled (Firefox bug 1729291)

HTTP

• The cache directive of the Clear-Site-Data response header has been disabled by default. It can be enabled using the preference privacy.clearsitedata.cache.enabled (Firefox bug 1729291).

Changes for add-on developers

• Support for partitionKey, the first-party URL of a cookie when it's in storage that is partitioned by top-level site, is added to {{WebExtAPIRef('cookies.get')}}, {{WebExtAPIRef('cookies.getAll')}}, {{WebExtAPIRef('cookies.set')}}, {{WebExtAPIRef('cookies.remove')}}, and {{WebExtAPIRef('cookies.cookie')}}. (Firefox bug 1669716)
• When a context menu is activated, {{WebExtAPIRef('menus.OnClickData','menus.OnClickData.srcUrl')}} returns the raw value of the src attribute of the clicked element, instead of the current URL (after redirects). (Firefox bug 1659155)