Aurora 12 is out – improvements and updated Developer Tools


Aurora 12 is out – improvements and updated Developer Tools

Aurora 12 is out, together with updated Developer Tools, and these are the improvements/changes.


A few of the improvements that stand out a little more:

ECMAScript Harmony’s Simple Map and Set builtins

For testing purposes, we have implemented ECMAScript Harmony’s Simple Map and Set builtins. This is only in Aurora and will be disabled when it goes to beta, so please test it out now and give feedback! There is also MDN documentation on Set and MDN documentation on Map if you want to learn more.

If you are more interested in Harmony progress, read up on our implementation work for ECMAScript 6

Support multitouch on Android

We’re happy to now have implemented multitouch for Firefox on Android!

Let authors put line breaks (newlines) in tooltips (title attribute)

It might seem like a small thing, but has been discussed quite some time. You can now use newlines for tooltips!

XMLHttpRequest should allow you to specify a network timeout in ms (for async requests)

Instead of timeouts and similar, this offers a way to specify a network timeout for XMLHttpRequests using the timeout attribute.

List of improvements

Here are all the improvements we’ve made complete with links to each bug listing for those who want to read up more on respective implementation.


  • When JavaScript is disabled, alternate content provided within the canvas element is not rendered and the canvas element still is rendered
  • Support multitouch on Android
  • Implement text/html for
  • Implement DOMError as defined in DOM 4
  • Let authors put line breaks (newlines) in tooltips (title attribute)


  • Implement Harmony simple Map and Set builtins
  • Implement ArrayBuffer.slice
  • Removed support for sharp variables


  • There is no Bidi/Joining algorithm on Arabic/Persian texts in MathML
  • Implement border-image revisions in latest css3-background
  • Implement column-fill property of CSS3 spec
  • remove handling of percentages as intrinsic widths/heights (SVG height=”100%” width=”100%” defaults)
  • getBoundingClientRect needs to take transforms into account
  • Adjust MathML text integration point treatment to comply with spec changes
  • Remove a pop loop from <rp> and <rt> handling, because the loop has been removed from the spec long ago
  • (munderover-align) [MathML3] munder, mover, munderover: add support for the align attribute
  • Implement CSS3 text-align-last
  • Add a ‘length’ property to DOMSVGStringList
  • SVGTests interface is not implemented


  • Implement crossOrigin attribute for <video> element (for webgl)


  • Return correct websocket close code when browser navigates away from page
  • Allow XHR to data URL
  • XMLHttpRequest should allow to specify a network timeout in ms (for async requests)


  • Log messages to console explaining media load algorithm failure

Developer Tools

There has been a total of 89 improvements to Web Console, Scratchpad, Style Editor, Page Inspector, Style Inspector, HTML view and Page Inspector 3D view (Tilt). Here are the highlights:

  • Errors and messages that were logged before the Web Console was opened are displayed when the console is opened up to a queue size limit
  • Scratchpad now includes Find and uses the standard platform key binding (ctrl-F/cmd-F)
  • Scratchpad now includes Jump to Line and uses the standard platform key binding ctrl/cmd-J
  • Style Editor now includes transitions
  • Style Editor adds in a closing brace for new rules to avoid disrupting the rest of the CSS
  • You can now remove nodes from the Page Inspector 3D view by pressing ‘x’. This makes it easier to visually select the node you want.
  • Normal close window keybinding works for Style Editor
  • Page Inspector highlighter now updates its position as the page changes
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