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Firefox 83 for developers - Mozilla | MDN
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Firefox 83 for developers
This article provides information about the changes in Firefox 83 that will affect developers. Firefox 83 was released on November 17, 2020.
Note: See also Firefox 83 is upon us on Mozilla hacks
Changes for web developers
Developer Tools
- When using the
:screenshothelper command in the Web Console, the--dprparameter is no longer ignored when taking a fullscreen screenshot using--fullpage(Firefox bug 1645284). - Developers can use the
scrollbadge in the Page Inspector to Debug scrollable overflow. Selecting the badge highlights elements that are causing overflow and marks them with theoverflowbadge (Firefox bug 1669129).
HTML/XML
- The
crossoriginattribute is now supported for<link rel=icon>(Firefox bug 1661075). - The
displaystyleattribute is now implemented for all MathML elements (Firefox bug 1666075).
CSS
- The vendor prefixed
:-moz-any()is now aliased to the standard:is()CSS pseudo-class function (Firefox bug 1666086). - We've added support for CSS Conic Gradients (Firefox bug 1632351) and (Firefox bug 1175958).
JavaScript
Intl[@@toStringTag]has been added, returning a default value ofIntl(recent addition to the ECMA spec). (Firefox bug 1670053)
HTTP
No changes.
APIs
No changes.
WebDriver conformance (Marionette)
- We've removed preliminary support for
WebDriver:SwitchToShadowRoot, which hasn't been added to the WebDriver specification yet (Firefox bug 1662468). - We fixed a bug in
WebDriver:BackandWebDriver:Forwardthat caused Marionette to hang when the navigation was triggered from within an<iframe>that gets removed (Firefox bug 1672758).
Changes for add-on developers
No changes.