Firefox 3.6 offers support for new and developing web standards, increased performance, and an overall better experience for web users and developers. This page provides links to articles covering the new capabilities of Firefox 3.6.
For web site and application developers
CSS
- Using gradients
- Firefox 3.6 adds support for the proposed -moz-linear-gradientand-moz-radial-gradientproperties forbackground.
- Multiple backgrounds
- The backgroundproperty (as well asbackground-color,background-image,background-position,background-repeat, andbackground-attachment) now supports multiple backgrounds. This lets you specify multiple backgrounds that are rendered atop one another in layers.
- Mozilla-specific media features
- Media features have been added for Mozilla-specific system metrics, so that media queries can be used to more safely check on the availability of features such as touch support.
- Scaling background images
- The background-sizeproperty from the CSS 3 Backgrounds and Borders draft is now supported under the name-moz-background-size.
- WOFF font support
- @font-facenow supports the WOFF downloadable font file format.
- Pointer events
- The pointer-eventsproperty lets content specify whether or not an element may be the target of mouse pointer events.
Miscellaneous CSS changes
- The remlength unit from CSS3 Values and Units is now supported. bug 472195
- image-renderingis supported for images, background images, videos and canvases. bug 423756
- text-align:end is now supported. bug 299837
- DOM changes to elements using the table displaytypes now work much better.
- Added :-moz-locale-dir(ltr)and:-moz-locale-dir(rtl)to make it easier to customize layouts based on whether the user interface is being displayed using a left-to-right or a right-to-left locale. bug 478416
- Added support for the :indeterminatepseudo-class, which matchescheckboxinputelements whoseindeterminateattribute istrue.
- Windowed plugins are no longer displayed in CSS transforms, because they can't be transformed properly by the compositor.
HTML
- Using files from web applications
- Support for the new HTML5 File API has been added to Gecko, making it possible for web applications to access local files selected by the user. This includes support for selecting multiple files using the input type="file"HTML element's newmultipleattribute.
- HTML5 video supports poster frames
- The posterattribute is now supported for thevideoelement, allowing content to specify a poster frame to be displayed until the video begins to play.
- Checkboxes and radio buttons support the indeterminateproperty
- HTML inputelements of typescheckboxandradionow support the indeterminate property, which allows a third, "indeterminate" state.
- Canvas image smoothing can be controlled
- The new mozImageSmoothingEnabledproperty can be used to turn on and off image smoothing when scaling incanvaselements.
- Asynchronous script execution
- By setting the asyncattribute on ascriptelement, thescriptwill not block loading or display of the rest of the page. Instead thescriptexecutes as soon as it is downloaded.
JavaScript
Gecko 1.9.2 introduces JavaScript 1.8.2, which adds a number of language features from the ECMAScript 5 standard:
- Date.parse()can now parse ISO 8601 dates like YYYY-MM-DD.
- 
  The prototypeproperty of function instances is no longer enumerable.
DOM
- Web workers can now self-terminate
- Workers now support the nsIWorkerScope.close()method, which allows them to terminate themselves.
- Drag and drop now supports files
- The DataTransferobject provided to drag listeners now includes a list of files that were dragged.
- Checking to see if an element matches a specified CSS selector
- The new element.mozMatchesSelectormethod lets you determine whether or not an element matches a specified CSS selector. See bug 518003.
- Detecting device orientation
- Content can now detect the orientation of the device if it has a supported accelerometer, using the MozOrientationevent. Firefox 3.6 supports the accelerometer in Mac laptops.
- Detecting document width and height changes
- The new MozScrollAreaChangedevent is dispatched whenever the document'sscrollWidthand/orscrollHeightproperties change.
Miscellaneous DOM changes
- The getBoxObjectFor()method has been removed, as it was non-standard and exposed even more non-standard stuff to the web. See bug 340571. Also affects MooTools which uses this call for Gecko detection; this has been fixed in the latest version of MooTools, so be sure to update.
- The new mozInnerScreenXandmozInnerScreenYproperties on DOM windows have been added; these return the screen coordinates of the top-left corner of the window's viewport.
- The new mozScreenPixelsPerCSSPixelattribute on thensIDOMWindowUtilsinterface, accessible only to chrome, provides a conversion factor between CSS pixels and screen pixels; this value can vary based on the zoom level of the content.
- When the page's URI's document fragment identifier (the part after the "#" (hash) character) changes, a new hashchangeevent is sent to the page. See window.onhashchange for more information. bug 385434
- The attribute document.readyStateis now supported. bug 347174
- Support for HTML5's element.classListto allow easier handling of the class attribute. bug 501257
- localNameand- namespaceURIin HTML documents now behave like they do in XHTML documents:- localNamereturns in lower case and- namespaceURIfor HTML elements is- "http://www.w3.org/1999/xhtml".
- element.getElementsByTagNameNSno longer lowercases its argument, so upper-case ASCII letters in the argument make matches against HTML elements fail. The same is true for- document.getElementsByTagNameNS.
- Support has been added for addresses in geolocation via the nsIDOMGeoPositionAddressinterface and a new field added tonsIDOMGeoPosition.
- The window.getComputedStylefunction now returns quotes withinurl()values.
XPath
- The choose() XPath method is now supported
- The choose()method is now supported by our implementation of XPath.
For XUL and add-on developers
If you're an extension developer, you should start by reading Updating extensions for Firefox 3.6, which offers a helpful overview of what changes may affect your extension. Plug-in developers should read Updating plug-ins for Firefox 3.6.
New features
- Detecting device orientation
- Content can now detect the orientation of the device if it has a supported accelerometer, using the MozOrientationevent. Firefox 3.6 supports the accelerometer in Mac laptops.
- Monitoring HTTP activity
- You can now monitor HTTP transactions to observe requests and responses in real time.
- Working with the Windows taskbar
- It's now possible to customize the appearance of windows in the taskbar in Windows 7 or later. This has been disabled by default in Firefox 3.6.
Places
- Places queries can now use the redirectsModeattribute on thensINavHistoryQueryOptionsinterface to specify whether or not to include redirected pages in results.
- Added the new nsIFaviconService.expireAllFavicons()method to thensIFaviconServiceinterface.
Storage
- Locale-aware collation of data is now supported by the Storage API
- Gecko 1.9.2 added several new collation methods to provide optimized collation (sorting) of results using locale-aware techniques.
- Properties on a statement can now be enumerated
- You can now use a for..inenumeration to enumerate all the properties on a statement.
- mozIStorageStatement's getParameterIndex changed behavior between 3.5 and 3.6.
- See bug 528166 for details.
- Asynchronously bind multiple sets of parameters and execute a statement.
- See bug 490085 for details. Documentation coming soon.
Preferences
- The nsIContentPrefServiceinterface has two new methods:nsIContentPrefService.getPrefsByName()andnsIContentPrefService.removePrefsByName().
Themes
See Updating themes for Firefox 3.6 for a list of changes related to themes.
- Lightweight themes
- Firefox 3.6 supports lightweight themes; these are easy-to-create themes that simply apply a background to the top (URL bar and button bar) and bottom (status bar) of browser windows. This is an integration of the existing Personas theme architecture into Firefox.
Miscellaneous
- Firefox will no longer load third-party components installed in its internal components directory. This helps to ensure stability by preventing buggy third-party components from being executed. Developers that install components this way must repackage their components as XPI packages so they can be installed as standard add-ons.
- contents.rdfis no longer supported for registering chrome in extensions. You must now use the- chrome.manifestfile instead. See bug 492008.
- Added support for hiding the menu bar automatically. See bug 477256.
- Added support for the container-live-roleattribute to objects. See bug 391829.
- The tabs-closebuttonbinding has been removed. See bug 500971.
- Added support to nsISoundfor playing sounds based on events that have occurred. See bug 502799.
- The syntax for the nsITreeViewmethodsnsITreeView.canDrop()andnsITreeView.drop()has changed to support the new drag & drop API introduced in Gecko 1.9. See bug 455590.
- Added support to snap the mouse cursor to the default button of dialog or wizard on Windows, see bug 76053. This is processed automatically by dialog and wizard element. But if a XUL application creates a window using the windowelement and it has a default button, it needs to callnsIDOMChromeWindow.notifyDefaultButtonLoaded()during the window'sonloadevent handler.
- The nsILocalFileMacinterface has had two methods removed:setFileTypeAndCreatorFromMIMEType()andsetFileTypeAndCreatorFromExtension().
- The new NetUtils.jsmcode module provides an easy-to-use method for asynchronously copying data from an input stream to an output stream.
- The new openLocationLastURL.jsmcode module makes it easy to read and change the value of the "Open Location" dialog box's remembered URL while properly taking private browsing mode into account.
- On Windows, the nsIScreeninterface now reports 24 bit per pixel color depths when the graphics driver claims 32 bits, since 24 more accurately represents the actual number of color pixels in use.
- Menu bars can now be hidden on Windows, using the new autohideattribute on thetoolbarXUL element.
- The loadOneTabandaddTabmethods now accept a newrelatedToCurrentparameter and, in addition, allow the parameters to be specified by name, since nearly all of the parameters are optional.
- The "hidden" property is no longer supported in install manifests; it's no longer possible to prevent the user from seeing add-ons in the add-on manager window.
- The @mozilla.org/webshell;1component no longer exists; you need to use@mozilla.org/docshell;1instead.
- You can now register with the update-timer category to schedule timer events without having to instantiate the object that the timer will eventually call into; it will instead be instantiated when it's needed. See nsIUpdateTimerManager.registerTimer()for details.
- The NPN_GetValue()function no longer provides access to XPCOM through the variable valuesNPNVserviceManager,NPNVDOMelement, andNPNVDOMWindow. This is part of the work toward making plugins run in separate processes in a future version of Gecko.
- Plugins are no longer scriptable through XPCOM (IDL) interfaces, NPRuntime is the API to use for making plugins scriptable, and NPP_GetValue()is no longer called to with the valueNPPVpluginScriptableInstanceorNPPVpluginScriptableIID. This is part of the work toward making plugins run in separate processes in a future version of Gecko.
For Firefox/Gecko developers
Certain changes are only really interesting if you work on the internals of Firefox itself.
Interfaces merged
The following interfaces have been combined together:
- nsIPluginTagInfo2has been merged into- nsIPluginTagInfo.
- nsIPluginInstanceInternal,- nsIPPluginInstancePeer,- nsIPluginInstancePeer1,- nsIPluginInstancePeer2, and- nsIPluginInstancePeer3have all been merged into- nsIPluginInstance.
- nsIWindowlessPlugInstPeerhas been merged into- nsIPluginInstance.
- nsIPluginManagerand- nsIPluginManager2have been merged into- nsIPluginHost.
Interfaces removed
The following interfaces have been removed entirely because they were unused, unimplemented, or obsolete:
- nsIFullScreen
- nsIDOMSVGListener
- nsIDOMSVGZoomListener
- nsIInternetConfigService
- nsIDKey
- nsIEventHandler
- nsIJRILiveConnectPIPeer
- nsIJRILiveConnectPlugin
- nsIScriptablePlugin
- nsIClassicPluginFactory
- nsIFileUtilities
Interfaces moved
The following interfaces have been relocated from their previous IDL files into new ones:
- nsIDOMNSCSS2Propertiesis now located in its own IDL file (- dom/interfaces/css/nsIDOMCSS2Properties.idl).
- nsIUpdateTimerManageris now located in its own IDL file.
A large number of interfaces have been moved. See Interfaces moved in Firefox 3.6 for a complete list.
Other interface changes
The following assorted changes have been made:
- The nsIPlugininterface now inherits fromnsISupportsinstead ofnsIFactory.
- The nsIPluginHostinterface now inherits fromnsISupportsinstead ofnsIFactory.
- The nsIFrameinterface now inherits fromnsQueryFrameinstead ofnsISupports.
- The nsIDeviceContextmethodgetPaletteInfo()has been removed, as it was never implemented.
- The nsIScriptContextmethodreportPendingException()has been removed, since it was no longer being used.
Changes in accessibility code
- The EVENT_REORDERaccessibility event is now sent when the children of frames and iframes change, as well as when the main document's children change. See bug 420845.
- The nsIAccessibleTable.selectRow()now correctly removes any current selection before selecting the specified row.