Site Compatibility for Firefox 24

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.

CSS

cursor: -moz-zoom-in and -moz-zoom-out have been unprefixed

Unprefixed support for the -moz-zoom-in and -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.

Prefixed -moz-initial is no longer supported

Support for the prefixed -moz-initial keyword has been removed from Firefox 24. The unprefixed initial keyword can be used instead starting with Firefox 19.

DOM

Obsolete event methods have been removed

The routeEvent, enableExternalCapture, and 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, captureEvents and releaseEvents are kept for backward compatibility as Google's research revealed that many sites relied on those methods for feature detection.

The deprecated preventBubble and 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

The implementation of the obsolete HTMLCommandElement interface has been removed in favor of the standardized HTMLMenuItemElement interface. Firefox has never supported the <command> element, though.

ProgressEvent.initProgressEvent is no longer available in Web Workers

The obsolete ProgressEvent.initProgressEvent method is no longer available in Web Workers. This method in general use has already been removed from Firefox 22.

The focus and blur events are now FocusEvent

The focus and blur events have been updated to be instances of the FocusEvent interface instead of the Event interface. This will comply with the DOM Level 3 Events spec.

SVG

GetSVGDocument has been removed

The GetSVGDocument interface has been removed. No other browsers are exposing it on the window object. The getSVGDocument method on the <embed>, <iframe> and <object> elements is still available.

Video/Audio

HTMLMediaElement.mozLoadFrom has been removed

The mozLoadFrom method has been removed from the HTMLMediaElement interface. It was a non-standard Mozilla extension to load data from another media element.

Event Handling

Touch events support has been temporarily disabled on desktop

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.

Miscellaneous

Support for Sherlock search plug-ins has been deprecated

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.

Document Tags and Contributors

Contributors to this page: kscarfone, Yoshino, teoli
Last updated by: teoli,