Firefox 66 для разработчиков


Developer tools


  • 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).




No additions.



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 events

Media, Web Audio, and WebRTC

  • The MediaDevices method getDisplayMedia() (en-US), 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 (en-US) has been added to local outbound RTCRTPStreamStats (en-US) 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> (en-US) 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).




No changes.


No changes.

Changes for add-on developers

API changes

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

Manifest changes

No changes.

See also

Older versions