Firefox 24 was released on . While it has been developed to maintain compatibility as much as possible, the new version includes some changes affecting backward compatibility aimed at improving interoperability with the other browsers or following the latest Web standards. Here's the list of such changes — hope this helps whenever you test your sites or applications.
This article only explains the changes that may affect backward compatibility for Websites. For the other new features and changes, please read the following documents:
Follow @FxSiteCompat on Twitter for further updates.
cursor: -moz-zoom-in and
-moz-zoom-out have been unprefixed
Unprefixed support for the
-moz-zoom-out values for the
cursor property has been added. Those were originally Mozilla CSS extensions and are now a part of the CSS3 UI editor's draft. The prefixed values will be removed after a reasonable period of time.
-moz-initial is no longer supported
- Bug 807184 – Remove support for prefixed "-moz-initial" CSS keyword, now that we support it unprefixed
Obsolete event methods have been removed
- Bug 673919 – Remove routeEvent, enableExternalCapture and disableExternalCapture
- Bug 874003 – Remove preventBubble and preventCapture
- Bug 726933 – Warn about getPreventDefault being deprecated
disableExternalCapture methods on the
window object have been removed. They were non-standard Netscape-derived APIs deprecated since Firefox 3 and the implementation has been no-op (doing nothing). Meanwhile,
releaseEvents are kept for backward compatibility as Google's research revealed that many sites relied on those methods for feature detection.
preventCapture methods, which were in the earlier W3C draft, have also been removed. The
stopPropagation method can be used instead.
Additionally, the non-standard
getPreventDefault method, deprecated since Firefox 16, will be removed soon in favor of the
defaultPrevented property. If
getPreventDefault is used in a Web page, Web Console shows a warning about the deprecation.
HTMLCommandElement has been dropped
ProgressEvent.initProgressEvent is no longer available in Web Workers
blur events are now
GetSVGDocument has been removed
HTMLMediaElement.mozLoadFrom has been removed
mozLoadFrom method has been removed from the
HTMLMediaElement interface. It was a non-standard Mozilla extension to load data from another media element.
Touch events support has been temporarily disabled on desktop
- Bug 888304 – Content touch-events on Firefox-desktop should be disabled until we can support them properly
The touch events support introduced with Firefox 18 has been disabled on the desktop version of Firefox, as some popular sites including Google and Twitter are not working properly. Once the bug is fixed, the API will be enabled again. To enable it anyway, open
about:config and set the
dom.w3c_touch_events.enabled pref to
2. The mobile versions including Firefox for Android and Firefox OS are not affected by this change. Also, the API has been enabled on the Metro-style version of Firefox for Windows 8.
Support for Sherlock search plug-ins has been deprecated
- Bug 877135 – stop loading Sherlock files from disk
- Bug 862137 – stop supporting Sherlock search engines
- Bug 862148 – stop supporting installation of Sherlock plugins from the web
Starting with Firefox 24, Sherlock-format search engine plug-ins are no longer loaded from local files. Sherlock support and the
window.sidebar.addSearchEngine function, which allows Web pages to install Sherlock plug-ins, will also be removed in the near future, along with the removal of the non-standard
window.sidebar API. Web publishers should provide OpenSearch plug-ins instead.