Firefox 66 для разработчиков

• JavaScript getters can now be executed from the auto-completion popup in the Web Console (баг 1499289).
• The Window methods alert(), prompt(), and confirm() now work again in Responsive Design Mode, after a period of being broken (баг 1273997).

• UTF-8-encoded HTML (and plain text) files loaded from file: URLs are now supported without <meta charset="utf-8"> or the UTF-8 BOM, making it easier to work on such files locally before uploading them to a server. You still need to make sure that the server sends charset=utf-8 in the Content-Type HTTP header for such files, otherwise the detection mechanism used for local files would break incremental loading in the network case (баг 1071816).

Removals

• The x-moz-errormessage attribute has been removed from the <input> element (баг 1513890). You should use  Constraint validation features to implement custom validation messages instead.

• Scroll anchoring has been implemented in Firefox Desktop (but not mobile yet), which includes the overflow-anchor property (баг 1305957).
• We've implemented the case-sensitive attribute selector modifier, s (баг 1512386).
• Several logical property shorthands have landed, along with the flow-relative border radius properties:
  • padding-block and padding-inline (баг 1519847).
  • margin-block and margin-inline (баг 1519944).
  • inset, inset-block, and inset-inline (баг 1520229).
  • border-block-color, border-block-style, border-block-width, border-inline-color, border-inline-style, and border-inline-width (баг 1520236).
  • border-block and border-inline (баг 1520396).
  • border-start-start-radius, border-start-end-radius, border-end-start-radius, and border-end-end-radius (баг 1520684).
• We implemented the overflow-inline and overflow-block media queries (баг 1422235).
• grid-template-columns and grid-template-rows are now animatable, as per the rules set out in their specs (баг 1348519).
• We now support calc with percentages for table cells and column widths (баг 957915).
• The min-content and max-content keywords are now available unprefixed (баг 1322780). These can be set on:
  • width
  • height
  • flex-basis
  • min-width
  • max-width
  • min-height
  • max-height
  • min-block-size
  • min-inline-size
  • max-block-size
  • max-inline-size
  • block-size
  • inline-size

No additions.

Removals

• We removed support for the xml:base attribute (баг 903372).

No changes.

New APIs/changes

• Autoplaying audio will be blocked by default soon after 66 becomes the release version of Firefox (баг 1487844, see баг 1535667 for rollout details). The feature will be rolled out gradually to users until everyone has it.

DOM

• The HTMLSlotElement.assignedElements() method has been implemented (баг 1425685).
• The TextEncoder.encodeInto() method has been implemented (баг 1514664).

DOM events

• The InputEvent.inputType property has been implemented (баг 1447239).
• The Window.event and Event.returnValue properties — originally proprietary IE features, then also supported across other browsers for compatibility purposes — have been re-introduced in Firefox 66, after first being added in versions 63 and 64 respectively but then removed again due to compatibility issues. 
• From 66 onwards, when the KeyboardEvent.keyCode property of the keypress event object is 0, the value will be the same as KeyboardEvent.charCode. Conversely, when charCode is 0, it will be the same as keyCode. This mirroring behavior matches other browsers and is expected to solve most associated compatibility issues, however user agent sniffing might cause further issues in some JavaScript libraries. Note that in spec terms, we've switched from the split model to the conflated model (see How to determine keyCode for keypress events in the UI Event spec).

Media, Web Audio, and WebRTC

• The MediaDevices method getDisplayMedia(), available as navigator.mediaDevices.getDisplayMedia(), has been added and synchronized with the specification. This method lets you capture a screen or part of a screen as a MediaStream for manipulation or sharing (баг 1321221).
• As a step toward eventually deprecating the Firefox-specific getUserMedia()-based method for capturing screen and window contents, the non-standard mediaSource constraint now treats the values screen and window identically. Both now present a list of both screens and windows for the user to choose from (баг 1474376).
• qpSum has been added to local outbound RTCRTPStreamStats objects. This measures the total of the Quantization Parameter values for every frame sent or received on the video track. The higher this number, the more compressed the stream probably is (баг 1347070).
• In a step along the road toward implementing support for Feature Policy in a future Firefox update, getUserMedia() can no longer be used in situations in which there is no proper origin for the content, such as when called from a sandboxed <iframe> or from a data URL entered into the address bar by the user. For more specifics and details, see Security в MediaDevices.getUserMedia() (баг 1371741).

Removals

• The legacy WebRTC PeerConnection.getStats() method has been removed, along with associated types (баг 1328194).

• The default value of the Accept header has been changed to */* (баг 1417463).

No changes.

No changes.

Menus

• Extension menu items of the "bookmark" type will also appear in the Bookmarks sidebar (Ctrl + B) and Library window (Ctrl + Shift + B) (баг 1419195).

No changes.

• Site compatibility for Firefox 66