---
title: Firefox 63 for developers
slug: Mozilla/Firefox/Versions/63
tags:
- '63'
- Firefox
- Mise à jour
- Mozilla
translation_of: Mozilla/Firefox/Releases/63
---
{{FirefoxSidebar}}
Cet article fournit des informations à propos des changements dans Firefox 63 qui affecteront les développeurs. Firefox 63 a été publié le 23 octobre 2018.
Changements pour les développeurs web
Outils de développeurs
- L'onglet Polices dans la page de l'Inspecteur inclus maintenant un éditeur facilitant la visualisation et l'édition des paramètres des polices sur votre page. Voir l'édition des polices pour plus d'informations.
- L'Inspecteur d'Accessibilité est maintenant activé par défaut ({{bug(1482454)}}).
- Lorsque vous survolez un objet dans l'Inspecteur d'Accessibilité, l'élément est mis en évidence et son rôle et nom seront affichés dans une barre d'information dans la page ({{bug(1473030)}}).
- La ligne de commande dans la Console Web est maintenant immédiatement affichée après le flux de sortie de la console ({{bug(1136299)}}).
- Une nouvelle icône a été ajouté au contenu dans le Moniteur Réseau indiquant si une URL appartient à un trackeur connu — voir les Icônes de Sécurité ({{bug(1333994)}}).
- La valeur par défaut de
devtools.aboutdebugging.showSystemAddons est maintenant false, ce qui signifie que le système d'add-ons ne sera plus listé dans la page about:debugging. Vous pouvez changer les paramètres en vous rendant sur la page about:config ({{bug(1425347)}}).
- La barre d'outils du Mode Responsive Design a été simplifiée, et nous avons ajouté une option pour aligner la vue à gauche.
- L'Inspecteur inclus un lien vers la définition de la classe pour un élément personnalisé. ({{bug(1443923)}}).
HTML
- Ajout du support pour l'attribut
decoding de l'élément {{HTMLElement("img")}} ({{bug(1416328)}}); Voir aussi {{DOMxRef("HTMLImageElement.decoding")}}.
Suppressions
- Le lien de type
sidebar (rel="sidebar") n'est plus supporté. Si une ancre contient cet attribut, elle sera ignorée ({{bug(1452645)}}).
CSS
- Support for the {{CSSxRef(":defined")}} pseudo-class has been added ({{bug(1331334)}}).
- Support for {{CSSxRef("row-gap")}}, {{CSSxRef("column-gap")}} and {{CSSxRef("gap")}} has been added in Flexbox layout ({{bug(1398483)}}).
- Re-enabled support for webkit-prefixed pixel-density @media queries ({{bug(1444139)}}).
- Support added for the CSS Flexible Box Layout (Flexbox) properties {{CSSxRef("align-self")}}, {{CSSxRef("align-content")}}, and {{CSSxRef("align-items")}} as well as the {{CSSxRef("justify-content")}} property ({{bug(1472843)}}).
- Implemented the
path() function for {{CSSxRef("offset-path")}} ({{bug(1429298)}}).
- Implemented syntax improvements from the Media Queries Level 4 specification ({{bug(1472843)}}).
- Renamed
offset-* properties to {{CSSxRef("inset-block-start")}}, {{CSSxRef("inset-block-end")}}, {{CSSxRef("inset-inline-start")}}, and {{CSSxRef("inset-inline-end")}} ({{bug(1464782)}}).
- Added support for the prefers-reduced-motion media feature ({{bug(1365045)}}, {{bug(1475462)}}).
- Added flow relative values (
block, inline) for the {{CSSxRef("resize")}} property ({{bug(1464786)}}).
- Implemented flexbox layout for
safe & unsafe values in {{CSSxRef("align-self")}}, {{CSSxRef("align-content")}}, and {{CSSxRef("justify-content")}} ({{bug(1297774)}}).
- The logical properties (where appropriate) are now animatable ({{bug(1309752)}}).
Suppressions
- Removed
offset-block-start, offset-block-end, offset-inline-start and offset-inline-end; these have been renamed to inset-*, as described above ({{bug(1464782)}}).
SVG
Aucun changement.
JavaScript
- The {{JSxRef("Symbol.prototype.description")}} property has been implemented ({{bug(1472170)}}).
- The {{JSxRef("Object.fromEntries()")}} method has been added ({{bug(1469019)}}).
- When you try to access a property of an undefined object, the error message is now much improved. Considering the case where
x is undefined and you try to access x.y, instead of TypeError: x is undefined the console now returns the more descriptive x is undefined; can't access its "y" property ({{bug(1259822)}}).
Suppressions
- Experimental WebAssembly Module IndexedDB serialization support has been removed ({{bug(1469395)}}).
APIs
Nouvelles APIs
- The Shadow DOM ({{bug(1471947)}}) and Custom Elements ({{bug(1471948)}}) APIs have been enabled by default; See Web components for more details.
- The {{domxref("Media_Capabilities_API", "Media Capabilities API", "", "1")}} been implemented ({{bug(1409664)}}).
- The {{domxref("Clipboard", "Async Clipboard API", "", "1")}} has been implemented and enabled by default for all channels ({{bug(1461465)}}). As is the case with Chrome, Firefox currently implements only the {{domxref("Clipboard.writeText", "writeText()")}} and {{domxref("Clipboard.readText", "readText()")}} methods; however, unlike Chrome,
readText() is only available in browser extensions.
- The {{DOMxRef("SecurityPolicyViolationEvent")}} interface is now supported. It allows sending events when the {{HTTPHeader("Content-Security-Policy")}} is violated ({{bug(1472661)}}).
DOM
- The following portions of the {{domxref("Web_Animations_API", "Web Animations API", "", "1")}} have been enabled by default (see {{bug(1476158)}}):
- The {{DOMxRef("Animation")}} properties {{DOMxRef("Animation.ready", "ready")}} and {{DOMxRef("Animation.finished", "finished")}}, specifying the
Animation object's ready and finished {{JSxRef("Promise")}}s.
- The {{DOMxRef("Animation")}} object's {{DOMxRef("Animation.effect", "effect")}} property.
- The interfaces {{DOMxRef("KeyframeEffect")}} and {{DOMxRef("AnimationEffect")}}.
- The {{DOMxRef("Element.toggleAttribute()")}} method has been implemented ({{bug(1469592)}}).
- The historical, previously non-standard, {{DOMxRef("Event.returnValue")}} property is now supported for compatibility purposes ({{bug(1452569)}}).
- We implemented the {{DOMxRef("Window.event")}} property to improve web compatibility, now that it's become standard ({{bug(218415)}}).
- To bring Firefox into alignment with Edge and Chrome, the {{DOMxRef("NavigatorID.platform", "navigator.platform")}} property now returns
"Win32" even when running on 64-bit Windows ({{bug(1472618)}}).
- Prior to Firefox 63, links that open new windows that had
rel="noopener", as well as calls to {{DOMxRef("Window.open()")}} with the noopener window feature enabled would default to having all window features disabled, so that you had to explicitly re-enable any standard features you wanted. Now these windows have the same set of features enabled as any other window, and you need to explicitly turn off any you don't want ({{bug(1419960)}}).
Evénements du DOM
- Handling of the Alt key on the right side of the keyboard has been improved on Windows. If the user's current keyboard layout maps the Alt key to the AltGr modifier key, the value of {{DOMxRef("KeyboardEvent.key")}} is now reported as
"AltGraph". This behavior matches the behavior recently introduced in Chrome ({{bug(900750)}}).
- Microphone access now works simultaneously in multiple tabs, even within the same content process ({{bug(1404977)}}).
- {{DOMxRef("RTCDataChannel")}} has been updated to support the sctp-sdp-21 data format for the data, in addition to the older sctp-sdp-05 format previously supported.
- The {{DOMxRef("ConstantSourceNode")}} node type for Web Audio API now has a default channel count of 2 rather than 1, in order to match the specification ({{bug(1413283)}}).
- The {{domxref("Web_Audio_API", "Web Audio API", "", "1")}} interface {{DOMxRef("AudioScheduledSourceNode")}} (and by extension, all the other node types based on it) now throw the correct exception when a negative value is specified for the node start time. That error is
RangeError ({{bug(1413284)}}).
- The minimum and maximum permitted values for an {{DOMxRef("AudioParam")}} object's {{DOMxRef("AudioParam.value", "value")}} have been changed to the minimum negative single-precision floating-point value (-340,282,346,638,528,859,811,704,183,484,516,925,440) and the maximum positive single-precision floating-point value (+340,282,346,638,528,859,811,704,183,484,516,925,440) respectively ({{bug(1476695)}}).
- The {{DOMxRef("SourceBuffer.changeType")}} method, which allows you to change codecs during an active stream, has been enabled by default. This is part of the {{domxref("Media_Source_Extensions_API", "Media Source Extensions API", "", "1")}} ({{bug(1481166)}}).
- The {{DOMxRef("AudioParam.setValueCurveAtTime()")}} method has been updated to correctly accept an array of floating-point values to indicate the parameter's values to change to over time. Previously, it required a {{DOMxRef("Float32Array")}} ({{bug(1421091)}}).
- {{DOMxRef("AudioParam.setValueCurveAtTime()")}} has also been updated to correctly return a proper
TypeError when a non-finite value is found in the values array ({{bug(1472095)}}).
- In addition,
setValueCurveAtTime() has been updated to ensure that, when the parameter finishes following the specified value curve after the duration elapses, the value of the parameter is set to the last value in the list of values to curve through ({{bug(1308436)}}).
- The
RTCRTPStreamStats dictionary has been renamed to {{DOMxRef("RTCRtpStreamStats")}} for consistency with other WebRTC dictionaries and the specification ({{bug(1480498)}}).
- Support for the
RTCRtpStreamStats dictionary's {{DOMxRef("RTCRtpStreamStats.kind", "kind")}} property has been added ({{bug(1481851)}}).
- The {{DOMxRef("RTCRtpStreamStats")}} dictionary's {{DOMxRef("RTCRtpStreamStats.isRemote", "isRemote")}} property is deprecated and will be removed in Firefox 65. A warning is now output to console when this property is accessed. See this blog post on the Advancing WebRTC blog for details ({{bug(1393306)}}).
Canvas et WebGL
- A new
powerPreference context attribute has been added to {{DOMxRef("HTMLCanvasElement.getContext()")}}. On macOS this allows WebGL non-performance-critical applications and applets to request the low-power GPU instead of the high-power GPU in multi-GPU systems ({{bug(1349799)}}).
Suppressions
- The obsolete and non-standard Firefox-only methods {{DOMxRef("Window.back()")}} and {{DOMxRef("Window.forward()")}} have been removed. Please use the {{DOMxRef("History.back", "window.history.back()")}} and {{DOMxRef("History.forward", "window.history.forward()")}} methods instead ({{bug(1479486)}}).
- The {{DOMxRef("URL.createObjectURL", "createObjectURL()")}} and {{DOMxRef("URL.revokeObjectURL", "revokeObjectURL()")}} methods are no longer available on {{DOMxRef("ServiceWorker")}} instances due to the potential they introduced for memory leaks to occur ({{bug(1264182)}}).
- Since it was deprecated in the specification anyway, the limited support for Doppler effects on {{DOMxRef("PannerNode")}} has been removed from the Web Audio API. The {{DOMxRef("AudioListener")}} properties {{DOMxRef("AudioListener.dopplerFactor", "dopplerFactor")}} and {{DOMxRef("AudioListener.speedOfSound", "speedOfSound")}} have been removed, along with the
PannerNode method {{DOMxRef("PannerNode.setVelocity", "setVelocity()")}} ({{bug(1148354)}}).
CSSOM
Aucun changement.
HTTP
- The {{HTTPHeader("Clear-Site-Data")}} header is implemented and no longer behind a preference ({{bug(1470111)}}).
Sécurité
- Site favicons are now subject to Content Security Policy, if one is configured for the site ({{bug(1297156)}}).
- CSP
script-src directive's 'report-sample' expression now recognized when generating violation reports. This directive indicates that a short sample of where the violation occurred should be included in the report. Previously, Firefox always included this sample ({{bug(1473218)}}).
- Firefox now uses NSS 3.39 ({{bug(1470914)}}).
Plugins
Aucun changement.
Nouvelles fonctionnalités
- Marionette now returns a
setWindowRect capability in the WebDriver:NewSession response that is true if the browser window can be repositioned and resized, which e.g. is the case for Firefox but not any mobile applications ({{bug(1470659)}}).
- Added support for the
unhandledPromptBehavior capability, which allows to define a specific prompt behavior of the WebDriver specification ({{bug(1264259)}}).
- Handling of user prompts has been added to the
WebDriver:ExecuteScript and WebDriver:ExecuteAsyncScript commands ({{bug(1439995)}}).
Changements API
- Deprecated command end-points without the
WebDriver: prefix have been removed ({{bug(1451725)}}).
- The
WebDriver:NewSession command returns recommended strings (linux, mac, windows) for platformName as defined in the WebDriver specification ({{bug(1470646)}}).
Corrections de bugs
- Focus related events were missing on element interaction when Firefox was not running as the top-most application ({{bug(1398111)}}).
- Performing a
pointerDown and pointerUp action in a subsequent action sequence could trigger a double click because WebDriver:ReleaseActions didn't reset the double click tracker ({{bug(1422583)}}).
- Executing
pause actions repeatedly could cause an infinite hang ({{bug(1447449)}}).
- Fixed a bug where returning an element collection from
WebDriver:ExecuteScript and WebDriver:ExecuteAsyncScript would cause a cyclic reference error ({{bug(1447977)}}).
- To prevent a race condition both the
WebDriver:AcceptAlert and WebDriver:DismissAlert commands now wait until the user prompt has been closed ({{bug(1479368)}}).
- Log entries as emitted by the frame script were no longer limited by
MarionettePrefs.logLevel but logged everything ({{bug(1482829)}}).
WebDriver:TakeScreenshot raised an error when taking a screenshot of a window larger than 32767 pixels in width or height ({{bug(1485730)}}).WebDriver:SendAlertText didn't replace default user prompt value if text to send is an empty string ({{bug(1486485)}}).
Autre
- Corrected the behavior of {{DOMxRef("PerformanceObserver.observe()")}} to simply do nothing if no valid entry types are found in the specified array of entry types to observe, or if the array is empty or missing. Previously, Firefox was incorrectly throwing a
TypeError ({{bug(1403027)}}).
- In OpenSearch, Firefox now accepts
application/json as a search URL type, as an alias of application/x-suggestions+json ({{bug(1425827)}}).
Changements des add-on développeurs
Changements API
Thèmes
- The default text color for {{WebExtAPIRef("browserAction")}} badges is now automatically set to black or white, to maximise contrast with the background ({{bug(1474110)}}).
- The
accentcolor and textcolor properties of the theme manifest key are now optional ({{bug(1413144)}}).
- {{WebExtAPIRef("browserAction.getBadgeTextColor()")}} and {{WebExtAPIRef("browserAction.setBadgeTextColor()")}} enable you to get and set the text color of browser action badges ({{bug(1424620)}}).
- The theme
colors key in manifest.json now supports the ntp_text property to set the text color in a new tab, and the ntp_background property to set the color of a new tab ({{bug(1347204)}}).
- Themes can now define the colors for sidebars, such as the bookmarks sidebar ({{bug(1418602)}}). The relevant properties include:
sidebar: The background color for sidebars.sidebar_text: The text color for sidebars.sidebar_highlight: The background color of a selected item in a sidebar.sidebar_highlight_text: The text color of a selected item in a sidebar.
- The method {{WebExtAPIRef("management.install()")}} allows web extensions to install and enable signed browser themes ({{bug(1369209)}}).
Recherche
- The new {{WebExtAPIRef("search")}} API enables you to retrieve the list of installed search engines and perform searches with them ({{bug(1352598)}}).
- {{WebExtAPIRef("topSites.get()")}} now takes an
options parameter enabling you to set various options for the list of sites returned ({{bug(1445836)}}).
Onglets
- {{WebExtAPIRef("tabs.onHighlighted")}} now supports multi-select ({{bug(1474440)}}).
- {{WebExtAPIRef("tabs.highlight")}} now includes an optional field in the
highlightInfo object — populate — which defaults to true. Setting it to false prevents the returned windows.Window object from being populated with a list of tabs, to improve performance ({{bug(1489814)}}).
- {{WebExtAPIRef("tabs.update")}} now supports changing the selection status of a tab by including
highlighted: true in the updateProperties parameter ({{bug(1479129)}}).
- {{WebExtAPIRef("tabs.update")}} supports changing the selection status of a tab without changing the focused tab ({{bug(1486050)}}) by including both
highlighted: true and active: false in the updateProperties parameter.
- {{WebExtAPIRef("tabs.query")}} now returns an array of {{WebExtAPIRef("tabs.Tab")}} objects if multiple tabs are selected ({{bug(1465170)}}).
- The {{WebExtAPIRef("tabs.Tab")}} property now properly reflects which tabs in a browser window are selected (highlighted) and {{WebExtAPIRef("tabs.highlight")}} supports changing the highlighted status of multiple tabs ({{bug(1464862)}}).
- The
isarticle property in the extraParameters object passed into {{WebExtAPIRef("tabs.onUpdated")}} has been renamed to isArticle. The old name is retained but deprecated. This change was uplifted to Firefox 62 ({{bug(1461695)}}).
- The {{WebExtAPIRef('tabs.onUpdated')}} event can be used to track when a tab is drawing the user's attention with
attention property of the changeInfo object ({{bug(1396684)}}).
- Added {{WebExtApiRef("menus.getTargetElement()")}} to the {{WebExtApiRef("menus")}} API. The method returns the clicked on element referenced by the
targetElementId parameter ({{bug(1325814)}}).
- {{WebExtAPIRef("menus.create()")}} now enables you to create invisible menu items, and {{WebExtAPIRef("menus.update()")}} enables you to toggle menu item visibility ({{bug(1482529)}}).
- Items created using the {{WebExtAPIRef("menus")}} API now support access keys ({{bug(1320462)}}).
- The
targetUrlPatterns parameter of {{WebExtApiRef("menus.create()")}} and {{WebExtApiRef("menus.update()")}} now supports any URL scheme, even those that are usually not allowed in a match pattern ({{bug(1280370)}}).
Autre
- {{WebExtAPIRef("commands.onCommand")}} is now treated as user input ({{bug(1408129)}}).
- The {{WebExtAPIRef("webRequest")}} API now enables you to filter for speculative connections ({{bug(1479565)}}).
- {{WebExtAPIRef("webRequest.SecurityInfo")}} adds two new properties,
keaGroupName and signatureSchemeName. This change was uplifted to Firefox 62 ({{bug(1471959)}}).
- {{WebExtAPIRef("cookies.Cookie")}} now includes a property indicating the SameSite state of the cookie. The {{WebExtAPIRef("cookies.SameSiteStatus")}} enumeration defines SameSite state values ({{bug(1351663)}}).
- Match patterns for URLs now explicitly match the "data" URL scheme ({{bug(1280370)}}).
Voir aussi
Anciennes versions
{{Firefox_for_developers(62)}}