Firefox 21 for developers

Web 开发者需要注意的变化

实现了<style>元素上的scoped属性。拥有该属性的<style>元素可以通过在 Firefox 20 中实现的 CSS 伪类:scope选择器选择到.(bug 508725).
实现了新的<main>元素 (bug 820508).

-moz-user-select属性的属性值在设置为 none 时和设置为 -moz-none 时效果等同于，这样才能让 Gecko 和其他内核 WebKit(Chrome, Safari),Presto (Opera) 以及 Trident(Internet Explorer) 中的表现相同 (bug 816298).
On XHTML content, the auto value of -moz-hyphens incorrectly applied hyphenation rules when the language was not explicitly declared. This is fixed by (bug 702121).
CSS 属性-moz-orient (en-US)现在支持新的值 auto. 当应用到一个<meter>元素或者<progress>元素上时，auto 就等同于 horizontal(bug 835883).

实现了window.location上的 origin 属性 (bug 828261).
实现了 <input type="time"> 对象上的 valueAsDate 和 valueAsNumber 方法 (bug 781570).
实现了 <input type="time"> 对象上的 min 和 max 属性 (bug 781572).
Some new keyCodes for volume control are supported (bug 674739).
Some new keyCodes for ancient keyboard layout such as AS/400 are now supported on Windows and Linux (bug 833719).
Various keyCode values for OEM sepecific keys on Windows are now supported again (bug 833719).
实现了window.crypto.getRandomValues函数 (bug 440046)。

更新 CSP 实现到最新的 CSP 规范 1.0(CR):
- Support for the spec-compliant Content-Security-Policy HTTP header (in addition to the experimental X-Content-Security-Policy) has been added (bug 783049). Note: the patch for this new header landed in Firefox 21, it is disabled on builds (bug 842657).

FUEL applications cannot use the Livemarks service anymore (bug 834492). The Livemarks service is deprecated and phased out in favor of the new async interface.
History API saw numerous deprecated API being removed:
- Replaced by mozIAsyncFavicons:
  - nsIFaviconService::setFaviconUrlForPage
  - nsIFaviconService::setFaviconData
  - nsIFaviconService::getFaviconData
  - nsIFaviconService::getFaviconForPage
  - nsIFaviconService::setAndLoadFaviconForPage
  - nsIFaviconService::getFaviconImageForPage
  - nsIFaviconService::getFaviconDataAsDataURL
- Replaced by mozIAsyncLivemarks:
  - nsILivemarkService::*
  - PlacesUtils.itemIsLivemark
  - PlacesUtils.nodeIsLivemarkContainer
  - PlacesUtils.nodeIsLivemarkItem
- Removed only third argument:
  - PlacesUIUtils.showBookmarkDialog
- No more implemented by Places, use mozIAsyncHistory instead:
  - nsIGlobalHistory2::addURI
  - nsIGlobalHistory2::isVisited
  - nsIGlobalHistory2::setPageTitle
- No more needed, use onDeleteURI or onItemRemoved:
  - nsINavHistoryObserver::OnBeforeDeleteURI
  - nsINavBookmarkObserver::OnBeforeItemRemoved
- Never implemented properly:
  - nsINavHistoryFullVisitResultNode
- Deprecated, use mozIAsyncHistory::updatePlaces instead:
  - nsINavHistoryService::AddVisit