Autoprefixer
Parse CSS and add vendor prefixes to CSS rules using values
from the Can I Use.
Write your CSS rules without vendor prefixes (in fact, forget about them
entirely):
:fullscreen a {
transition: transform 1s
}
Process your CSS by Autoprefixer:
var prefixed = autoprefixer.compile(css);
It will use the data on current browser popularity and properties support
to apply prefixes for you:
:-webkit-full-screen a {
-webkit-transition: -webkit-transform 1s;
transition: transform 1s;
}
:-moz-full-screen a {
transition: transform 1s;
}
:fullscreen a {
-webkit-transition: -webkit-transform 1s;
transition: transform 1s;
}
Twitter account for news and releases:
@autoprefixer.
Sponsored by Evil Martians.
Translations
На русском: статья про Автопрефиксер на Хабрахабре
Features
Forget about prefixes
The best tool is a tool you can't see and one that does the work for you.
This is the main idea behind Autoprefixer.
Autoprefixer interface is simple: just forget about vendor prefixes
and write normal CSS according to latest W3C specs. You don’t need
a special language (like Sass) or special mixins.
Because Autoprefixer is a postprocessor for CSS,
you can also use it with preprocessors, such as Sass, Stylus or LESS.
Actual data from Can I Use
Autoprefixer uses the most recent data from Can I Use,
understands which browsers are actual and popular and adds only the necessary
vendor prefixes.
It also cleans your CSS from old prefixes (like prefixed border-radius
,
produced by many CSS libraries):
a {
-webkit-border-radius: 5px;
border-radius: 5px
}
compiles to:
a {
border-radius: 5px
}
Rewrite syntax
Flexbox or gradients have different syntaxes in different browsers
(sometimes you need to recalculate angles, sometimes you need 2 old properties
instead of new one), but Autoprefixer hides this from you.
Just code by latest W3C specs and Autoprefixer will produce the code
for old browsers:
a {
display: flex;
}
compiles to:
a {
display: -webkit-box;
display: -webkit-flex;
display: -moz-box;
display: -ms-flexbox;
display: flex
}
Fast
Autoprefixer is about 16 times faster than Compass and 8 times faster
than Stylus.
On a Core i7 with 10 GB of RAM and SSD, benchmark with GitHub styles is:
~/Dev/autoprefixer$ ./node_modules/.bin/cake bench
Load GitHub styles
Autoprefixer: 316 ms
Compass: 5342 ms (16.9 times slower)
Rework: 249 ms (1.3 times faster)
Stylus: 2548 ms (8.1 times slower)
Unlike -prefix-free, Autoprefixer
compiles CSS once on deploy and doesn’t hit client-side performance.
Browsers
You can specify the browsers you want to target in your project:
autoprefixer("last 1 version", "> 1%", "ie 8", "ie 7").compile(css);
last n versions
is last versions for each browser. Like “last 2 versions”
strategy in
Google.> n%
is browser versions, selected by global usage statistics.ff > 20
and ff >= 20
is Firefox versions newer, that 20.none
don’t set any browsers to clean CSS from any vendor prefixes.- You can also set browsers directly.
Blackberry and stock Android browsers will not be used in last n versions
.
You can add them by name:
autoprefixer("last 1 version", "bb 10", "android 4").compile(css);
You can find the browsers codenames in data file:
android
for old Android stock browser.bb
for Blackberry browser.chrome
for Google Chrome.ff
for Mozilla Firefox.ie
for Internet Explorer.ios
for iOS Safari.opera
for Opera.safari
for desktop Safari.
By default, Autoprefixer uses > 1%, last 2 versions, ff 24, opera 12.1
:
- Firefox 24 is a latest ESR.
- Opera 12.1 will be in list until Opera supports non-Blink 12.x branch.
Inspect
You can check which browsers are selected and which properties will be prefixed:
inspect = autoprefixer("last 1 version").inspect();
console.log(inspect);
Or by CLI command:
autoprefixer -i
FAQ
Does it add polyfills for old browsers?
No. Autoprefixer only adds prefixes, not polyfills. There are two reasons:
- Prefixes and polyfills are very different and need a different API.
Two separate libraries would be much better.
- Most of IE polyfills are very bad for client perfomance. They use slow hacks
and old IEs is mostly used on old hardware. Most of CSS 3 features that is
only used for styling should be ignored in old IEs as it is recommended in
Graceful Degradation.
Why doesn’t Autoprefixer do anything?
Developers are often surprised by how few prefixes are required today.
If Autoprefixer doesn’t add prefixes to your CSS, check if they’re still
required on Can I Use.
If a prefix is required, but Autoprefixer doesn’t add it or adds it
incorrectly, please
report an issue
and include your source CSS and expected output.
Does it support source maps?
Unfortunately, right now Autoprefixer doesn’t support source maps.
However, this feature will be included in the next version, 1.0, which is
currently under development
and is planned for release in mid-December 2013.
Right now you can use lydell’s fork with source map support:
lydell/autoprefixer.
You can check the current status of this feature in
autoprefixer#37.
Why Autoprefixer plugin for text editor changed my indents?
Rework, which Autoprefixer currently
uses for parsing CSS, doesn’t save indents, because it was created for Grunt
and other build tools.
In version 1.0 Autoprefixer will switch to the
PostCSS parser, which preserves formatting
of the code.
Usage
Ruby on Rails
Add autoprefixer-rails gem
to Gemfile
and write CSS in a usual way:
gem "autoprefixer-rails"
Middleman
Add middleman-autoprefixer
gem to Gemfile
:
gem "middleman-autoprefixer"
and activate the extension in your project’s config.rb
:
activate :autoprefixer
Ruby
You can integrate Autoprefixer into your Sprockets environment
by autoprefixer-rails
gem:
AutoprefixerRails.install(sprockets_env)
or process CSS from plain Ruby:
prefixed = AutoprefixerRails.compile(css)
Grunt
You can use the
grunt-autoprefixer
plugin for Grunt. Install the npm package and add it to Gruntfile:
grunt.loadNpmTasks('grunt-autoprefixer');
If you use Sass with compress
output style and worry that Autoprefixer might
uncompress CSS, try grunt-csso.
It will compress the CSS back, but does the compression much better than Sass.
Prepros
If you want to build your assets in GUI, try
Prepros. Just set “Auto Prefix CSS”
checkbox
in right panel.
Compass
If you use Compass binary to compile your styles, you can easily integrate
Autoprefixer with it. Install autoprefixer-rails
gem:
gem install autoprefixer-rails csso-rails
and add post-compile hook to config.rb
:
require 'autoprefixer-rails'
require 'csso'
on_stylesheet_saved do |file|
css = File.read(file)
File.open(file, 'w') do |io|
io << Csso.optimize( AutoprefixerRails.compile(css) )
end
end
If you use compress
output style, Autoprefixer will uncompress CSS.
For this reason, we use csso-rails
to compress CSS back (it compress much better than Sass).
If you need uncompressed CSS, remove Csso.optimize
method call.
You can set browsers array as second argument in AutoprefixerRails.compile
.
Stylus
If you use Stylus CLI, you can add Autoprefixer by
autoprefixer-stylus plugin.
Just install npm package and use it in -u
option:
stylus -u autoprefixer-stylus file.css
Mincer
To use Autoprefixer in Mincer,
install autoprefixer
npm package and enable it:
environment.enable('autoprefixer');
Node.js
Use autoprefixer
npm package:
var autoprefixer = require('autoprefixer');
var prefixed = autoprefixer.compile(css);
JavaScript
You can use Autoprefixer in the browser or a non-Node.js runtime
with standalone version.
Rework
Autoprefixer can be also used as a
Rework
filter, so you can combine it with other filters:
rework(css).
use( autoprefixer(['> 1%', 'opera 12.5']).rework ).
use( rework.references() ).
toString();
PHP
You can use Autoprefixer in PHP by
autoprefixer-php library:
$autoprefixer = new Autoprefixer();
$css = 'a { transition: transform 1s }';
$prefixed = $autoprefixer->compile($css);
Sublime Text
You can process your styles directly in Sublime Text with the
sublime-autoprefixer
plugin.
Others
You can use the autoprefixer
binary to process CSS files using
any assets manager:
sudo npm install --global autoprefixer
autoprefixer *.css
See autoprefixer -h
for help.
In-package Update
It’s highly recommended that you always use the latest version of Autoprefixer.
If by any chance you or your company are not able to update the package
(e.g. in case of long test periods before any library updates), you can still
update the very browser data that Autoprefixer fetches from Can I Use:
autoprefixer --update
Note that the in-package update doesn’t get any code fixes nor the
implementation of new features. It just keeps the browser popularity and
support data up to date, and adds new browser versions.