Firefox 68 for developers
This article provides information about the changes in Firefox 68 that will affect developers. Firefox 68 was released on July 9, 2019.
- The Web console now shows more information about CSS warnings, including a node list of the DOM elements that used the rule (bug 1093953).
- You can now filter content in the Web console using regular expressions (bug 1441079).
- The Browser console now allows you to show or hide messages from the content process by setting or clearing the checkbox labeled Show Content Messages (bug 1260877).
- You can now Search in all files in the current project from the debugger by pressing
F(Windows or Linux) or
F(macOS) (bug 1320325).
- The Network monitor request list now allows you to block a specific URL (bug 1151368).
- You can now resend a network request without editing the method, URL, parameters, and headers, using the Resend command on the context menu (bug 1422014).
- The context menu of the Network monitor Headers tab now allows you to copy all or some of the header information to the clipboard in JSON format (bug 1442249).
- A button has been added to the rules panel of the Page inspector that allows you to toggle the display of any print media queries (bug 1534984).
- The fonts panel now includes a slider to modify
- A warning icon appears next to unsupported CSS properties or rules that have invalid values, to help you understand why certain styles are not being applied (bug 1306054).
- You can now delete local and session storage entries by selecting the item in the storage inspector and pressing the backspace key (bug 1522893).
- The Accessibility Inspector now includes a new Check for issues feature, which will include a number of audit tools to highlight accessibility problems on your web pages. The first available check is contrast, for highlighting color contrast problems.
- The preference that controls the visibility of internal extensions (system add-ons and hidden extensions) on the about:debugging page has been changed from
- Responsive design mode has been redesigned — the Device Settings dialog (device selection menu > Edit List...) is now more intuitive and simpler to use (bug 1487857).
<track>element — represented by
HTMLTrackElement— now receives a
cuechangeevent in addition to the
TextTrackitself, if the text track is a contained by a media element (bug 1548731).
<link>elements support the
disabledattribute again, albeit with different behavior. When
disabledis set on a
<link>element along with
rel="stylesheet", the referenced stylesheet is not loaded during page load, and will be loaded on demand when the
disabledattribute is changed to
falseor removed (bug 1281135).
- CSS Scroll Snapping has been updated to the latest version of the specification (bug 1312163) and (bug 1544136), this includes:
-webkit-line-clampproperty has been implemented for compatibility with other browsers (bug 866102).
- Support has been added for the
::markerpseudo-element (bug 205202) and animation for
::markerpseudos (bug 1538618)
- We changed
currentcolorto be a computed value (except for the
colorproperty) (bug 760345).
- Support has been fixed for the
chlength unit so it now matches the spec (fallback for no '0' glyph, vertical metrics) (bug 282126)
counter-setproperty has been implemented. (bug 1518201).
- We now implement list numbering using a built-in "list-item" counter; this fixes list numbering bugs (bug 288704).
- Selector matching and parsing support has been implemented for
::part()(bug 1545430) and (bug 1545425).
- CSS Transforms are now supported in indirectly rendered things e.g.)
While we're keeping the prefixed versions of the various gradient properties (
repeating-radial-gradient()available for compatibility reasons, we have revised how they're parsed so that they're handled much more like the non-prefixed versions. This means that certain existing styles won't work correctly. In particular, the complicated syntax taking both an angle and a position will no longer work, and the
tokeyword in the
<side-or-corner>parameter is not required for the prefixed gradient properties. You are encouraged to use the standard, non-prefixed gradient properties instead, as they're now widely supported (bug 1547939).
CSS Object Model (CSSOM)
- The legacy
removeRule()methods have been added to the
CSSStyleSheetinterface. These were introduced by Internet Explorer 9 and have never managed to quite be stamped out, so they have been added to improve compatibility with the small percentage of sites that still use them (bug 1545823).
- The Visual Viewport API has now been enabled by default on Android (bug 1512813). Adding this API to desktop versions of Firefox is being tracked in bug 1551302.
noreferreris now supported; if specified, the new window's content is loaded without sharing the hostname, IP address, URL, or other identifying information about the host device (bug 1527287).
HTMLImageElementis now implemented. This can be used to trigger loading and decoding of an image prior to adding it to the DOM (bug 1501794).
XMLHttpRequesthas been updated to no longer accept the non-standard
responseType. Code still using it should be updated to use the Fetch API as a stream (bug 1120171).
XMLHttpRequestnow outputs a warning to console if you perform a synchronous request while handling an
pagehideevent (bug 980902).
cookieproperty has moved from the
HTMLDocumentinterface to the
SVGElement.focus()methods now accept an optional object that may contain a boolean
preventScrolloption specifying whether or not to block the browser from scrolling the newly-focused element into view (bug 1374045).
- Firefox for Android no longer incorrectly sends a
resizeevent until after the first frame is painted; this improves web compatibility with sites that don't expect this event to occur (bug 1528052).
- The dispatching of events for non-primary mouse buttons has been made to more closely follow the specification; the
clickevent is no longer sent when non-primary buttons are clicked, instead using
auxclick. In addition,
dblclickno longer fires for non-primary buttons (bug 1379466).
- The proprietary
MouseEvent.mozPressureproperty has been deprecated, and will now trigger a warning in the console (bug 1165211).
Media, Web Audio, and WebRTC
- Due to changes in the Google Play store's policies, starting with Firefox 68 for Android, the OpenH264 codec used to handle AVC/H.264 video in WebRTC connections can no longer be downloaded and installed. Therefore, fresh installs of Firefox on Android devices no longer support AVC in WebRTC calls. If you upgrade from earlier versions of Firefox and already have the codec downloaded, it will continue to work. This does not affect other platforms. For more details, see this article on SUMO or bug 1548679.
- WebRTC has been updated to recognize that a
nullcandidate passed into the
icecandidateevent handler, indicating the receipt of a candidate, instead indicates that there are no further candidates coming; when this happens the ICE gathering (
iceGatheringState) state reaches
getSynchronizationSources()now support video tracks; previously they only worked on audio (bug 1534466).
- The Web Audio API
MediaStreamTrackAudioSourceNodeinterface is now supported, as is the method
RTCDataChannel.negotiatedis now implemented (bug 1529695).
MediaStreamAudioSourceNode()constructor has been updated to match the current specification's definition that the "first audio track" in the stream is the track whose ID comes first in lexicographical order (bug 1324548).
getUserMedia()may no longer be used from a non-secure context; attempting to do so now throws a
NotAllowedErrorexception. Secure contexts are those loaded using HTTPS, those located using the
file:///scheme, and those loaded from
localhost. For now, if you must, you can re-enable the ability to perform insecure calls to
getUserMedia()by setting the preference
- The HTTP
Clear-Site-Dataheader no longer supports the
executionContextsdirective. This was removed due to problems with interactions between interconnections among different kinds of data at different points in the navigation process and the way the specification is designed. It has been proposed that this directive be removed from the specification for this reason, among others (bug 1548034).
- Due to CVE-2019-11730: Same-origin policy treats all files in a directory as having the same-origin, changes have been made so that Firefox now treats files in the same directory as being from different origins. This has a number of side-effects on what will work in documents loaded via file:// URLs (see bug file-fallout for useful background research). For example, workers can no longer be loaded.
WebDriver:SwitchToWindowchanges the selection to a different window it now waits for its
activateevents before returning (bug 1335085).
- Fixed the
TypeError: this.tabModal is nullfailure, which sometimes appeared when interacting with modal dialogs or user prompts (bug 1538782)
- Disabled the feature to force unloading background tabs on low memory conditions, to prevent top-level browser contexts from magically disappearing (bug 1553748).
- Disabled privileged content processes that caused HTTP authentication dialogs not to appear when navigating to a website after opening a new tab (bug 1558763).
proxy.unregister()functions have been deprecated and will be removed from Firefox 71 (bug 1545811).
incognito, has been added to the proxy.RequestDetails. object. When
true, it indicates that this was a private browsing request (bug 1545163).
- The webRequest.RequestFilter parameters can include an incognito parameter. If provided, requests that do not match the incognito state (
false) will be filtered out (bug 1548177).
cookieStoreId, representing the cookie store ID of the current context, has been added to the proxy.RequestDetails. object (bug 1545420).
- When an add-on attempts to add a bookmark folder to the root folder, the resulting error message is now much more intuitive (bug 1512171).
- The promise returned by
browser.tabs.duplicate()now resolves immediately, before the tabs are completely loaded (bug 1394376).
- Support has been added for chrome.storage.managed, allowing web extension settings to be implemented via enterprise policy (bug 1230802).
- Hacks release post: Firefox 68: BigInts, Contrast Checks, and the QuantumBar
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