Firefox 18 was released on January 8, 2013. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.
reversedattribute of the
<ol>element is now supported (Firefox bug 601912).
crossoriginattribute of the
<link>element is now supported (Firefox bug 786564).
allowfullscreenattribute of the
<iframe>has been implemented and it's prefixed predecessor
mozallowfullscreenis now deprecated.
min-heightnow uses the
autokeyword as initial value (This has an effect only on flex items as it resolves to
0, the previous initial value, for other items). (Firefox bug 763689)
- The cascade has been updated: now author
!importantrules override CSS animations. (Firefox bug 783714)
backgroundshorthand property now recognizes CSS3
background-sizeproperty specified inside. (Firefox bug 570326)
- Initial support for the CSS Flexbox Module has been landed. It is disabled by default but can be enabled by setting
layout.css.flexbox.enabledto true (Firefox bug 666041).
navigator.mozPayhas been landed. (Firefox bug 767818)
window.devicePixelRatiohas been landed. (Firefox bug 564815)
- The MacOS X backend for
window.navigator.batteryhas been implemented. (Firefox bug 696045)
MozBlobBuilderis removed. Developers need to use
Blobconstructor for creating a
Blobobject. (Firefox bug 744907)
visibilitychangeevent and the Page Visibility API has been unprefixed (Firefox bug 812086).
TextEncoderhave been added. Note that the implementation and spec of these evolved and have been changed in Firefox 19 (Firefox bug 764234).
HTMLMediaElement.srchas been separate in two properties: the standard
srcproperty, dealing with strings, and the prefixed
mozSrcObjectproperty, dealing with media streams (Firefox bug 792665).
- Support for transferable objects.
Screen.lockOrientation()method now supports an
Arrayof strings as argument (Firefox bug 784549.
- Harmony's (ECMAScript 2015) Direct Proxies have been landed (Firefox bug 703537). Warning: the implementation contains a couple of known bugs, missing features and misalignments with the current state of the spec. Do not rely on it for production code.
- The ECMAScript 2015
contains()method is now implemented on strings. This is unfortunately not compatible with Mootools 1.2, which expects different behavior from
contains()on strings but does not ensure it. Newer versions of Mootools fix this issue; sites should upgrade their Mootools version to something newer than 1.2.
The 4th parameter (aOffset) of
onDataAvailable()method changes to unsigned long long. (Firefox bug 784912)
setUploadStream()supports over 2GB content-length (Firefox bug 790617)
addEditorObserver()has been removed, use
removeEditorObserver()no longer takes a
nsIEditorObserverparameter (Firefox bug 785091)
http-on-modify-requestobservers are no longer guaranteed to be called synchronously during
nsIChannel.asyncOpen(). For observers that need to be called during
asyncOpen(), the new
http-on-opening-requestobserver topic has been added.
See(Firefox bug 800799)
resolvemethod has been removed. Now, only the
asyncResolvemethod can be used. See (Firefox bug 769764)
The following interfaces have been removed.
- 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