Web developers, it is time to celebrate! In the upcoming Firefox 16, which reached the Aurora status today, a major enhancement is the unprefixing of several stable CSS features. Other notable features of interest to Web developers include several more HTML5-related APIs, better accessibility on Mac OS, and improvements to Firefox Developer Tools.

So which CSS features are unprefixed?

Pay attention to the gradient syntax

While the syntax of CSS animations, transitions and transforms has not changed lately, that is not the case of the CSS gradients syntax, which is significantly different than in most prefixed implementations.

The definitive syntax for linear gradients is :

<linear-gradient> = linear-gradient( [ [ <angle> | to <side-or-corner> ] ,]? <color-stop>[, <color-stop>]+ ) <side-or-corner> = [left | right] || [top | bottom]

If we break it down, its structure is :

linear-gradient( direction , color-stop )

As the color-stop syntax hasn’t evolved lately, the direction parameter is where most of the latest changes happened.

The direction parameter can be defined either using a CSS <angle> , or using the to keyword followed by one or two keywords describing the side or the corner.

That’s the major change! This to keyword wasn’t there before and it reverses the direction that was use previously: -prefix-linear-gradient( top left ) becomes linear-gradient( to bottom right ) .

Also the <angle> changed: before, 0deg pointed to the right; now it points, consistently with other angles in the CSS spec, to the top. Like this:

So here again, you need to change -prefix-linear-gradient(0deg) to linear-gradient(90deg) . Failure to adapt the angle will lead to the gradient to be oriented differently, like this:

→

Similar changes have been made to the radial gradient syntax, with a newly introduced at keyword.

More HTML5 & friends goodies

Unprefixing mature CSS features is not the only improvement in the area of supporting standards:

IndexedDB has reached Candidate Recommendation status and has been unprefixed too. This is amazing.

has reached Candidate Recommendation status and has been unprefixed too. This is amazing. Support for the HTML5 Microdata API landed.

landed. Support for the HTML5 <meter> element landed.

element landed. We unprefixed the Battery API .

. We unprefixed the Vibration API .

. We improved our media queries support by adding support for the dppx unit.

unit. The CSS properties height and width are now animatable.

and are now animatable. The CSS animations can be “reversed“: the reverse and alternate-reverse keywords have been added.

and keywords have been added. Our implementation of JavaScript improved with several new features in Harmony (the maybe future EcmaScript 6): Support for direct proxies Support for the Array ‘s spread operator Improvement of Number , supporting now toInteger() , isInteger() and isFinite()

Improvement of Keyboard (still prefixed as mozKeyboard ), now supporting setSelectedOption() , setValue() and onfocuschange() .

Accessiblity

A giant step has been done in making Firefox more accessible. Support for VoiceOver on Mac OS has landed. It was the last platform where our accessibility features where severely behind. This is very exciting for all people needing such features on the Mac. More information.

Developers Tools

Last but not least, we continued to improved our developer tools!

Now you can toggle a developer toolbar: go to Tools > Web Developer > Developer Toolbar, or press Shift-F2. The toolbar itself looks like this:

The toolbar has a command line interface and also nice buttons to the right to quickly reach useful tools. The command line interface is easy to expand and more commands are expected in the future. Typing help in it displays the supported commands.

The Web Console also has been improved and displays now a nifty error count.

Finally our Scratchpad gained a list of recently opened files. Always convenient.

Other notable changes

See more details in the release notes and in Firefox 16 for developers.

Conclusion

Firefox 16 is on the way to being a very strong release for Web developers, both on the support of standards, and with the nice improvements in our tools, maturing quickly. In the future, Web sites will be easier to do and more powerful!