Software Update: Mozilla Developer Preview 1.9.3 alpha 2

The Mozilla Foundation is releasing a glimpse of the new Gecko engine and accompanying Firefox 3.7 with Mozilla Developer Preview 1.9.3 Alpha 2. This alpha release is primarily aimed at developers so that they can try out the new capabilities of both the engine and browser and test current creations to see if they work correctly. New is, among other things, that plugins, such as Flash and Silverlight, are isolated from the browser, so that a stuck or crashing plugin no longer kills Firefox. The announcement of this alpha release looks like this:

Mozilla Developer Preview (1.9.3 alpha 2)

The Mozilla Developer Preview of Gecko 1.9.3 alpha 2 is an early developer milestone containing new features of the Gecko layout engine. It is being made available for testing purposes only, and is intended for web application developers and our testing community. Current users of Mozilla Firefox should not use this Mozilla Developer Preview.

New Features and Changes

Gecko 1.9.3 Alpha 2 introduces new features which can be tested by using this Mozilla Developer Preview. Many of these features are still in development, and while they will likely appear in some future version of Mozilla Firefox, some may be in earlier releases than others.

Plugins:
On Windows and Linux, plugins (such as Flash and Silverlight) are now isolated from Firefox. Plugin crashes will not kill Firefox itself, and unresponsive plugins are automatically restarted.

Security:
The SSL security system has been changed to fix a renegotiation flaw. For technical details, see the newsgroup posting announcing the change.

Performance:
Link history lookup is now performed asynchronously on a thread. This results in less I/O during page load and improves overall browser responsiveness.
Loading the HTML5 specification no longer causes very long browser pauses. See bug 526394 for details.
Strings are not copied between the main DOM code and web workers, improving performance for threaded JavaScript which moves large pieces of data between threads.
Repainting HTML in SVG

javascript:
The JavaScript engine has many improvements: string handling is improved, faster closures, and some support for fast tracing and JIT of recursive functions.

HTML:
The placeholder attribute for and is now supported.<br>Support for the HTML5 History.pushState() and History.replaceState() methods and the popstate event. See bug 500328 for details.

User Interface:
The stop and reload buttons have been merged when they are adjacent on the toolbar. See bug 343396 for details.

SVG:
Support for SMIL Animation in SVG. Support for animating some SVG attributes is still under development and the animatedMotion element isn’t supported yet.

stability:
Crash reports from plugin processes are now submitted automatically. Crash report submission can be disabled in Firefox preferences (Advanced / General / Submit crash reports).

C.S.S:
Support for CSS Transitions. This support is not quite complete: support for animation of transforms and gradients has not yet been implemented.
Support for the -moz-image-rect() value for background-image. See bug 113577 for more details.

WebGL:
Support for WebGL, which is disabled by default but can be enabled by changing a preference. See this blog post and this blog post for more details.

stupid:
Support for the getClientRects and getBoundingClientRect methods on Range objects. See bug 396392 for details.
Support for the setCapture and releaseCapture methods on DOM elements. See bug 503943 for details.

We are interested in feedback on any bugs or missing capabilities in these new features. Some of the changes will affect web and platform compatibility. For detailed information about compatibility changes in Gecko 1.9.3, please read Upcoming Firefox features for developers.