Aurora 17 it out, bringing better security and support for new standards

A new version of Firefox Aurora is released every six weeks. Every release includes important features for web developers like you, such as security improvements and support for new HTML5 and CSS3 features.

Aurora 17 brings significant improvements to standards support:

  • The :dir(...) pseudo-class of Selectors Level 4, which allows you to easily style content differently based on text direction. This is more powerful than the attribute selector [dir=...], which only matched the value of the attribute and could not take inheritance or other factors into account. This will make it easier for you to write stylesheets friendly to both left-to-right and right-to-left languages.
  • The new @supports pseudo-class, which allows you to test support for specific CSS properties and values. This helps you fall back gracefully when a feature is not supported. The pseudo-class is unprefixed, but is only available behind a preference (layout.css.supports-rule.enable) because the specification is still young. Other vendors are in the procress of implementing this specification as well, so we expect it to move forward quickly towards the CR status. Wide support will greatly ease feature direction in the future.
  • The WheelEvent event of DOM Events Level 3. This is an important step towards DOM compatibility, and especially event compatibility. Until now, browsers implemented two non-interoperable wheel events, MouseWheelEvent and MouseScrollEvent. This move toward WheelEvent will lead to better interoperability once all other browsers support it. Support for the associated onwheel attribute has also been implemented.
  • CSS Animations are now calculated asynchronously, resulting in significant performance improvements.
  • Experimentally, Gecko now supports the inputmode attribute of the HTML <input> element. The supported values different from those defined by the WhatWG, but the draft is still young and discussions are ongoing.
  • Two big changes related to SVG: support for the FillPaint attribute and support for the StrokePaint attribute. More importantly, SVG display lists have been implemented.
  • JavaScript improvements through continued implementation of Harmony, the experimental EcmaScript 6 draft. Maps and Sets are now iterable, and the new string methods startsWith(), endsWith(), and contains() are now supported.
  • Blobs finally support ZIP content.

Aurora 17 also brings two major security-related changes:

  • Support for the sandbox attribute of the <iframe> element. This lets you manage the security risk of embedding content in a page. For example, you could grant full privileges to an <iframe> that contains content you control, but fewer rights to an <iframe> that uses content from a third party, like an advertising service.
  • New handling of certain dialogs. In particular, prompt, alert, and confirm dialogs can no longer be launched from onunload, onbeforeunload, or onpagehide. Though there are some legitimate uses of this type of behavior, many Web sites were abusing it to prevent users from leaving a page.

On the media side, we continue to improve our implementation of the Opus codec. For example, we now support multiple channels audio. These improvements are especially important due to upcoming real-time communication features.

As with all recent Firefox releases, Aurora includes improvements to our developer tools:

  • A new Markup panel in the Page Inspector, allowing you to easily edit the DOM.
  • Improvements that make the Web Console, Debugger and Developer Toolbar faster and easier to use.

This is an especially strong release in terms of user interface improvements.

Numerous improvements have been made to Mac OS integration:

  • When available, Firefox now uses the Notification Center (in Mac OS Mountain Lion) instead of Growl to send notifications.
  • The background color of the tab bar now changes when inactive, just like other native Mac OS applications.
  • Light windows now have a new light color, matching the Mac OS theme.

Users will also see improvements when copying images to other programs. Until now, copying from the content area to a program like Photoshop caused transparency information to be lost. This is no longer the case!

Still on the user experience side, the look of location bar results has been greatly improved. Additionally, when fixed content is present in the header, scrolling with Page-DOWN and Page-UP now works correctly, allowing continuous reading and a far better scrolling experience.

Like always, responsiveness and memory management have continued to improve this cycle. Even though no major changes were made, numerous small improvements have been made to make Firefox a little bit snappier as a whole.

Again, this is a very strong Aurora release. As always, the final set of features released with Firefox 17 (scheduled for November 20th, 2012) may change slightly due to testing and user feedback, but nonetheless this is a very strong start.

View full post on Mozilla Hacks – the Web developer blog

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