New developer features in Firefox 3

For web site and application developers

Updating web applications for Firefox 3

Provides information about changes you may need to make to your web site or web application to take advantage of new features in Firefox 3.

Online and offline events

Firefox 3 supports WHATWG online and offline events, which let applications and extensions detect whether or not there's an active Internet connection, as well as to detect when the connection goes up and down.

Alternate style sheets

Firefox 3 supports the CSS object model alternate style sheet API.

Web-based protocol handlers

You can now register web applications as protocol handlers using the navigator.registerProtocolHandler() method.

Drawing text using a canvas

You can now draw text in a canvas using a non-standardized API supported by Firefox 3.

Transform support for canvas

Firefox now supports the transform() and setTransform() methods on canvases.

Using microformats

Firefox now has APIs for working with microformats.

Drag and drop events

Firefox 3 supports new events that are sent to the source node for a drag operation when the drag begins and ends.

Focus management in HTML

The new HTML 5 activeElement and hasFocus attributes are supported.

Offline resources in Firefox

Firefox now lets web applications request that resources be cached to allow the application to be used while offline.

CSS improvements in Firefox 3

Firefox 3 features a number of improvements in its CSS support.

DOM improvements in Firefox 3

Firefox 3 offers a number of new features in Firefox 3's DOM implementation, including support for several Internet Explorer extensions to the DOM.

JavaScript 1.8 support

Firefox 3 offers JavaScript 1.8.

EXSLT support

Firefox 3 provides support for a substantial subset of the EXSLT extensions to XSLT.

SVG improvements in Firefox 3

SVG support in Firefox 3 has been upgraded significantly, with support for over two dozen new filters, several new elements and attributes, and other improvements.

Animated PNG graphics

Firefox 3 supports the animated PNG (APNG) image format.

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For XUL and extension developers

Updating extensions for Firefox 3

Provides a guide to the things you'll need to do to update your extension to work with Firefox 3.

FUEL Library

FUEL is about making it easier for extension developers to be productive, by minimizing some of the XPCOM formality and adding some "modern" JavaScript ideas.

XUL improvements in Firefox 3

Firefox 3 offers a number of new XUL elements, including new sliding scales, the date and time pickers, and spin buttons.

Templates in Firefox 3

Templates have been significantly improved in Firefox 3. The key improvement allows the use　of custom query processors to allow data sources other than RDF to be used.

Embedding XBL bindings

You an now use the data: URL scheme to embed XBL bindings directly instead of having them in separate XML files.

Localizing extension descriptions

Firefox 3 offers a new method for localizing add-on metadata. This lets the localized details be available as soon as the add-on has been downloaded, as well as when the add-on is disabled.

Securing updates

In order to provide a more secure add-on upgrade path for users, add-ons are now required to provide a secure method for obtaining updates before they can be installed. Add-ons hosted at AMO automatically provide this.

Idle service

Firefox 3 offers the new nsIIdleService interface, which lets extensions determine how long it's been since the user last pressed a key or moved their mouse.

Using nsILoginManager

The Password Manager has been replaced by the new Login Manager.

Full page zoom

Firefox 3 improves the user experience by offering full page zoom in addition to text-only zoom.

Interfacing with the XPCOM cycle collector

XPCOM code can now take advantage of the cycle collector, which helps ensure that unused memory gets released instead of leaking.

The Thread Manager

Firefox 3 provides the new nsIThreadManager interface, along with new interfaces for threads and thread events, which provides a convenient way to create and manage threads in your code.

JavaScript modules

Firefox 3 now offers a new shared code module mechanism that lets you easily create modules in JavaScript that can be loaded by extensions and applications for use, much like shared libraries.

Places

The history and bookmarks APIs have been completely replaced by the new Places API.

Making the transition to Places

An article about how to update an existing extension to use the Places API.

Download Manager improvements in Firefox 3

The Firefox 3 Download Manager features new and improved APIs, including support for multiple progress listeners.

Using nsILoginManager

The Password Manager has been replaced by the new Login Manager.

Using content preferences

Firefox 3 includes a new service for getting and setting arbitrary site-specific preferences that extensions as well as core code can use to keep track of their users' preferences for individual sites.

Notable bugs fixed in Firefox 3

This article provides information about bugs that have been fixed in Firefox 3.

feature for pinging a URL is now supported, and is enabled by default.