Changes for Web developers
- The HTML5
<data>element has been implemented (bug 839371).
- The HTML5
<time>element has been implemented (bug 629801).
rangestate of the
<input type="range">) has been implemented, behind the preference
dom.experimental_forms_range, only enabled by default on Nightly and Aurora channel (bug 841948).
- The support for the
<template>element, part of the Web component specification has been implemented (bug 818976).
- ES6 Arrow Function syntax has been implemented (bug 846406).
- The new Object.is function has been added (bug 839979).
argumentsin generator expressions is now inherited from enclosing lexical scope (bug 848051).
- The ES6 Proxy
preventExtensionstrap have been implemented (bug 789897).
- Support for the
XMLHttpRequesthas been removed. This was a Gecko-only feature that was never standardized. Server-Sent Events, Web Sockets or inspecting
responseTextfrom progress events can be used instead.
- Support for Web Notifications has been landed (bug 782211).
appendmethod now accepts a third optional
filenameparameter (bug 690659).
Node.isSupportedhas been removed (bug 801562).
Node.getUserDatahas been removed for web content and are deprecated for chrome content (bug 842372).
Element.attributesproperty has been moved there from
Nodeas required by the spec (bug 844134).
- The Mac OS X backend for
Ambient Light Eventshas been implemented.
- Elements in the HTML namespace with local names
<image>no longer implement the
NodeIterator.detachmethod has been changed to do nothing (bug 823549).
BlobEventinterface has been implemented (bug 834165).
- The properties
HTMLInputElement.inputmodehas been removed to match the spec in
HTMLInputElement.inputMode, respectively (bug 847370 and bug 850346).
- WebRTC: the Media Stream API and Peer Connection API are now supported by default.
- Web Components: the
Document.registermethod has been implemented (bug 783129).
ProgressEvent.initProgressEvent()constructor method has been removed. Uses the standard constructor,
ProgressEvent()to construc and initialize
- Manipulated data associated with a
pasteevent can now be accessed via the
ClipboardEvent.clipboardDataproperty (bug 407983).
HTMLTimeElementinterface has been implemented (bug 629801).
- When a
Workerconstructor is passed an invalid URL, it now throws
- Support for CSS Flexbox layout has been enabled by default (bug 841876).
- Following a spec change, the initial value for
min-heighthas been changed back to
0, even on flex items (bug 848539).
- Support for CSS Conditionals (
CSS.supports) has been enabled by default (bug 855455).
- Support for
background-originproperties in the
backgroundshorthand has been implemented (bug 570896).
Changes for add-on and Mozilla developers
propertiesparameter has been removed from the
nsITreeView. These methods should now return a string of space-separated property names. (bug 407956)
inIDOMUtils.getCSSPropertyNames()method has been implemented and will return all supported CSS property names.
- See here for more changes.
Firefox Developer Tools
- Font inspector shows which fonts on your computer are applied to the page.
- Visual paint feedback mode shows when and where a page is repainted.
- The dev tools may now be docked to the right side, not just the bottom of the browser.
- Some panes within the dev tools have switched from XUL to HTML. For example, the css rule viewer is now chrome://browser/content/devtools/cssruleview.xhtml, not
cssruleview.xul. Instead of adding an overlay directly to extend features of these panes, you may add an overlay and script to the outer xul document, to add load listeners and change these html documents.
- The stack trace is now shown as a breadcrumb near the top, and the script listing is now at the left panel of the debugger.
- Firefox 21 for developers
- Firefox 20 for developers
- Firefox 19 for developers
- Firefox 18 for developers
- Firefox 17 for developers
- Firefox 16 for developers
- Firefox 15 for developers
- Firefox 14 for developers
- Firefox 13 for developers
- Firefox 12 for developers
- Firefox 11 for developers
- Firefox 10 for developers
- Firefox 9 for developers
- Firefox 8 for developers
- Firefox 7 for developers
- Firefox 6 for developers
- Firefox 5 for developers
- Firefox 4 for developers
- Firefox 3.6 for developers
- Firefox 3.5 for developers
- Firefox 3 for developers
- Firefox 2 for developers
- Firefox 1.5 for developers