Mozilla Firefox 40.0 Beta 1发布

Mozilla 发布 Mozilla Firefox 40.0 的 Beta 1 版本，基于 Gecko 40 内核开发，40 版本的最大改进是有望带来类似 Chrome 的多进程设计，这样可以提升内存的利用率从而提升性能和标签/窗口之间的稳定性(但最新的版本似乎并没有带来)，新设计的标签页可以自动判断和展示您认为感兴趣的内容，正式版本预计8月11日发布。

下载地址:

http://dm-download02.mozilla.org/pub/mozilla.org/mozilla.org/firefox/releases/40.0b1/

Web developersDeveloper Tools 方面的改进：

值得关注的更新：

Improvements to the Animations view

Get help from MDN for CSS property syntax

Edit filters in the Page Inspector

Web Console now shows messages from workers

Filter requests by URL in the Network Monitor

Many new context menu options in the Network Monitor

Show when network resources are fetched from the browser cache

Filter rules in the Page Inspector

其他：

Break at debugger; statements in unnamed eval sources

Copy URL/Open in New Tab context menu items for Debugger source list pane

console.dirxml support in the Web Console

Style Editor: "Open Link In New Tab" item added to stylesheet list

Inspector selector search now includes class/id results even without css prefix

Tooltips in box-model view saying which CSS rule caused the value

Switch between color unit format in the Inspector using Shift+click

Implement "Scroll Into View" menu item for the Inspector

Linkify url/id/resource attributes in the Inspector

IP address tooltip in the Network Monitor

完整改进：all devtools bugs fixed between Firefox 39 and Firefox 40.

CSS

Prefixed rules (-moz-) for text-decoration-color, text-decoration-line, and text-decoration-style have been removed (bug 1097922).

The property text-align now supports the match-parent value (bug 645642).

In Quirks Mode, empty-cells now defaults to show, like in standard mode (bug 1020400).

The -moz-orient non-standard property, used to style and element has been adapted for vertical writing-modes: the value auto has been dropped and the values inline and block added, with inline being the new default value (bug 1028716).

JavaScript

Unreachable code after return statement (including unreachable expression after semicolon-less return statements) will now show a warning in the console (bug 1005110, bug 1151931).

Symbol.match has been added (bug 1054755).

Passing an object which has a property named Symbol.match with a truthy value to String.prototype.startsWith, String.prototype.endsWith, and String.prototype.contains now throws a TypeError (bug 1054755).

RegExp function returns pattern itself if called without new and pattern object has a property named Symbol.match with a truthy value, and the pattern object's constructor property equals to RegExp function. (bug 1147817).

Support for the non-standard JS1.7 destructuring for-in has been dropped (bug 1083498).

Non-standard initializer expressions in for...in loops are now ignored and will present a warning in the console. (bug 748550 and bug 1164741).

\u{xxxxxx} Unicode code point escapes have been added (bug 320500).

String.prototype.contains has been replaced with String.prototype.includes, String.prototype.contains is kept as an alias (bug 1102219).

If the DataView constructor is called as a function without the new operator, a TypeError is now thrown as per the ES6 specification.

An issue regressed in Firefox 21, where proxyfied arrays without the get trap were not working properly, has been fixed. If the get trap in a Proxy was not defined, Array.length returned 0 and the set trap didn't get called. A workaround was to add the get trap even if was not necessary in your code. This issue has been fixed now (bug 895223).

WeakMap.prototype and WeakSet.prototype have been updated to be just ordinary objects, per ES6 specification (bug 1055473).

Interfaces/APIs/DOMNew APIs

The Push API has been implemented (bug 1038811).

Web Animations API

Improvement in our experimental Web Animations implementation, mostley to match latest spec changes:

AnimationPlayer.currentTime now can also be set (bug 1072037).

Animatable.getAnimationPlayers(), available on Element has been renamed to Element.getAnimations() (bug 1145246).

Animation and AnimationEffect have been merged into the newly created KeyframeEffectReadOnly (bug 1153734).

AnimationPlayer has been renamed to Animation (bug 1154615).

AnimationTimeline is now an abstract class, with DocumentTimeline its only implementation (bug 1152171).

CSSOM

The CSS Font Loading API is now enabled by default in Nightly and Developer Edition releases (bug 1088437). It is still deactivated by default in Beta and Release browsers.

The CSSCharsetRule interface has been removed and such objects are no longer available in CSSOM (bug 1148694). This matches the spec (recently adapted) and Chrome behavior.

WebRTC

WebRTC: the negotiationneeded event is now also sent for initial negotiations, not only for re-negotiations (bug 1149838).

DOM & HTML DOM

When unable to parse the srcset, the HTMLImageElement.currentSrc method doesn't return null anymore but "", as requested by the latest specification (bug 1139560).

Like for images, Firefox now throttle Window.requestAnimationFrame() for non-visible