Firefox 56 for developers

开发者工具

• 在CSS格检查器中显示以负号开始的行号(bug 1369942).

HTML

• 在打标签的窗体控件中采用labels 属性，比如 HTMLInputElement.labels (bug 556743).
• 实现了 <link rel="preload">; 更详细的内容，可以参见 Preloading content with rel="preload"  (bug 1222633). 需要注意的是，当前的Firefox只支持对可缓存的资源进行预加载。

CSS

• 实现了Mozilla自有的属性 <color> 值为 -moz-win-accentcolor 以及 -moz-win-accentcolortext (可以参见 bug 1344910), 以及专用的媒体查询语句 -moz-windows-accent-color-in-titlebar (参见bug 1379938).

SVG

无修改.

JavaScript

• The Intl API has been enabled on Firefox for Android (bug 1344625).

APIs

New APIs

No changes.

DOM

• On Mac, Document.hidden is now true when the window is behind another non-translucent application bug 1236512.
• The Gamepad.displayId property has been implemented (bug 1375816).
• The PerformanceTiming.secureConnectionStart property has been implemented (bug 772589).
• Firefox used to accept iso-2022-jp-2 sequences silently when an iso-2022-jp TextDecoder() was instantiated, however this has now been removed to simplify the API, as no other browsers support it and no pages seem to use it. (bug 715833).
• The 4ms clamping behaviour of setTimeout() and setInterval() has been updated to be more in line with other browsers, as described in Timeouts throttled to >=4ms (bug 1378586).
• The Page Visibility API's Document.onvisibilitychange handler has been added (bug 1333912).
• The Window.showModalDialog() method has been removed (bug 981796).

DOM events

• GlobalEventHandlers.onwheel is now available on HTMLElement — it wasn't before (bug 1370550).

WebRTC

• Firefox now supports the RTCPeerConnection properties which let you examine the current and pending configurations of the local and remote ends of the connection, to help manage changes in configuration: currentLocalDescription, pendingLocalDescription, currentRemoteDescription, and pendingRemoteDescription.

Canvas and WebGL

• The CanvasRenderingContext2D.drawImage() method has been updated so that smoothing occurs when downscaling even if imageSmoothingEnabled is false. This is not mandatory as per spec, but follows Chrome's behaviour. See bug 1360415.
• An SVGImageElement can now be used as a CanvasImageSource, e.g. as the image source in a drawImage() call (bug 1382027).

Security

No changes.

Plugins

No changes.

Other

• Gecko now encodes URLs internally as punycode, to avoid URL encoding problems (see bug 945240, also see discussion in bug 942074).
• Firefox on Windows and Mac OS X can now be made to run in headless mode using the -headless flag (see bug 1355150 and bug 1355147).

Removals from the web platform

HTML

• The <isindex> element has been removed from the HTML parser, and from form submission (bug 1266495).
• The <applet> element has been removed (bug 1279218).

APIs

No changes.

SVG

No changes.

Changes for add-on and Mozilla developers

WebExtensions

No changes.

See also

• Site Compatibility for Firefox 56