Firefox 114 release notes for developers

Changes for web developers

Developer Tools

• Fixed an issue where the Accessibility Inspector did not correctly show ARIA roles on elements, which affected how landmark roles were displayed. Roles that cannot be mapped to ARIA use a Gecko internal role name (Firefox bug 1572512).

HTML

No notable changes.

CSS

• The :lang() pseudo-class now uses string-matching semantics (including * wildcards) for matching language codes rather than prefix-matching semantics. Additionally, comma-separated lists of languages are now supported for matching multiple languages (Firefox bug 1121792).
• The -webkit-text-security property that lets you replace characters with shapes is now supported. You can now control the rendering of text security using this property (Firefox bug 1826629).
• The infinity and NaN constants are now supported inside the calc() function (Firefox bug 1830759).

JavaScript

• Workers now support loading ECMAScript modules. You can load modules into workers by specifying the {type: "module"} option in the Worker and SharedWorker constructors. Worker scripts can also statically or dynamically import modules using import and import(), respectively (Firefox bug 1812591).
• Worklets can now use import to statically import ECMAScript/JavaScript modules (Firefox bug 1812591).

SVG

• The crossorigin attribute is now supported in image and feImage elements (Firefox bug 1240357).

APIs

• Window.print() now opens a print dialog on Firefox for Android, allowing the current document to be printed (Firefox bug 1809922).

• The WebTransport API is now supported, which includes the following interfaces: WebTransport, WebTransportBidirectionalStream, WebTransportDatagramDuplexStream, WebTransportReceiveStream, WebTransportSendStream, WebTransportDatagramDuplexStream and WebTransportError. For more information see Firefox bug 1692754, Firefox bug 1818754, and Firefox bug 1791835.

• CSSImportRule.supportsText can now be used for getting any supports() conditions that were specified when using the @import at-rule (Firefox bug 1829590).

Removals

• The deprecated and non-standard mozImageSmoothingEnabled property is permanently removed. See the imageSmoothingEnabled property for smoothing in scaled images (Firefox bug 1228850).

WebDriver conformance (WebDriver BiDi, Marionette)

WebDriver BiDi

• Added support for the commands input.performActions and input.releaseActions, which can be used to emulate user input for interacting with elements on web pages. Similar to Marionette all the available input sources of the WebDriver specification are supported, which are key, pointer, and wheel (Firefox bug 1832380).
• Added support for custom browser to client messages, which allows to send a script.message event from within a script formerly installed via script.addPreloadScript (Firefox bug 1824187).
• Added support for the serializationOptions parameter for script.evaluate and script.callFunction to customize the RemoteValue serialization (Firefox bug 1824953).
• Fixed an issue where both the script.evaluate and script.callFunction commands did not include the stack trace and failed to properly build the exception details for a rejected Promise (Firefox bug 1829630).
• Fixed an issue where the browsingContext.domContentLoaded and browsingContext.load events did not report the correct url, when the page defined a <base> meta tag (Firefox bug 1825634).

Marionette

• Fixed an issue where the command WebDriver:GetComputedRole didn't properly return the WAI-ARIA roles (Firefox bug 1822112).
• Fixed an issue where modifier keys were not reset when they were used again within the same WebDriver:ElementSendKeys command (Firefox bug 1776190).

Changes for add-on developers

Removals

• Support for browser_style in the manifest keys action, options_ui, page_action, and sidebar_action is deprecated for Manifest V3 extensions (Firefox bug 1827910). See Manifest v3 migration for information about transitioning from browser_style in Manifest V3 extensions.