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    css-validator Build status

    Validate CSS via W3C's service

    This was created to validate CSS inside of the json2css test suite.

    Getting Started

    Install the module with: npm install css-validator

    var validateCss = require('css-validator');
    var assert = require('assert');
    validateCss({text: 'a { color: blue; }'}, function (err, data) {
      assert.strictEqual(data.validity, true);
      assert.deepEqual(data.errors, []);
      assert.deepEqual(data.warnings, []);


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    css-validator returns a single function as its module.exports

    validateCss(options, cb)

    Validate CSS against W3C's Jigsaw validation service

    • options String|Object - If options is a String, it will be treated as options.text
      • w3cUrl String - URL to validate against. Default is
      • The following options from the validator itself
      • uri null|String - URL of document to validate. CSS and HTML documents are allowed. Supports http and https protocols.
      • text null|String - CSS to validate
      • usermedium String - Medium where the CSS will be used (e.g. all, print, screen)
        • Service's default value: all
      • profile String - CSS profile to use for validation (e.g. css3svg, css21, svg)
        • Service's default value: css3svg
      • lang String - Language to use in response (e.g. en, bg, de)
        • Service's default value: en
      • warning Number|String - Warning level to set. Default is 2
        • Service's default value: 2
        • If set to no, no warnings will be returned
        • If set to 0, less warnings will be returned
        • If set to 1 or 2, more warnings will be returned
      • vextwarning String|Boolean - Allow vendor extensions to just show up as warnings
        • Possible values: false, true
        • Service's default value: false
    • cb null|Function - Error first callback with function (err, data) {} signature
      • err null|Error - If there was a connetivity error, this will be it
      • data null|Object - Container for response from jigsaw
        • validity Boolean - If there were no errors, this will be true. Otherwise, it is false.
        • errors Object[] - Array of errors
          • These are dynamically parsed and not guaranteed to exist. The service only guarantees line, level, and message.
          • line Number - Line where error occurred
          • errortype String
          • context String
          • errorsubtype String
          • skippedstring String - Content where error occurred
          • message String - Human readable information about the error and why it occurred
        • warnings Object[] - Array of warnings
          • line Number - Line where error occurred
          • level Number - Intensity of the warning. See options.warning for more info
          • message String - Human readable information about the warning and why it occurred

    If cb is not provided, a DuplexStream will be returned to you.

    If you have not provided options.uri or options.text, you can .write + .end OR .pipe to the stream CSS to validate.

    Additionally, you can use .read and .pipe to get the data returned by cb.

    The stream will emit the following events:

    • error Error - Error occurring during connection or parsing of response
    • data Object - Same as data sent to cb. Emitted once.
    • end - Emitted when we have finished parsing the input and outputting events
    • validity Boolean - Event for data.validity with data.validity as its data
    • validation-error Object - Event for a new data.errors object with the error as its argument
    • validation-warning Object - Event for a new data.warnings object with the warning as its argument


    css-validator offers a command line interface for validation:

    $ css-validator --help
      Usage: css-validator [options] <filepath ...>
        -h, --help                   output usage information
        -V, --version                output the version number
        --w3c-url <url>              URL to validate against. Default is
        --delay <ms>                 Delay between validation requests to avoid service blacklisting, defaults to 100ms
        --concurrency <concurrency>  Amount of requests to run in parallel, defaults to 1
        --usermedium <usermedium>    Medium where the CSS will be used (e.g. `all` (service default), `print`, `screen`)
        --profile <profile>          CSS profile to use for validation (e.g. `css3svg` (service default), `css21`, `svg`)
        --lang <lang>                Language to use in response (e.g. `en` (service default), `bg`, `de`)
        --warning <warning>          Warning level to set (e.g. `0`, `1`, `2` (service default), `no`)
        --vextwarning <vextwarning>  Allow vendor extensions to just show up as warnings. Possible values are: `true`, `false` (service default)


    var cssValidate = require('css-validator');
    var css = [
      "body {",
      "  background: url(ab'cd');",
      "  -moz-box-sizing: content-box;",
    cssValidate(css, function (err, data) {
      { validity: false,
       [ { line: '2',
           errortype: 'parse-error',
           context: ' body ',
           errorsubtype: '\n                                exp\n                            ',
           skippedstring: '\n                                url(ab \'cd\')\n                            ',
           message: '\n        \n                                Value Error :  background (nullcolors.html#propdef-background)\n        \n                                url(ab \'cd\') is not a background-color value : \n                            ',
           error: '\n                        ' } ],
       [ { line: '3',
           level: '0',
           message: 'Property -moz-box-sizing is an unknown vendor extension',
           warning: '\n                        ' } ] }


    In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint via npm run lint and test via npm test.


    As of Nov 27 2013, Todd Wolfson has released this repository and its contents to the public domain.

    It has been released under the UNLICENSE.


    npm i css-validator

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