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Style form elements when they are empty


Version published
Weekly downloads
decreased by-9.98%

Weekly downloads



PostCSS Blank Pseudo PostCSS Logo

npm version CSS Standard Status Build Status Discord

PostCSS Blank Pseudo lets you style form elements when they are empty, following the Selectors Level 4 specification.

input:blank { background-color: yellow; } /* becomes */ input[blank].js-blank-pseudo, .js-blank-pseudo input[blank] { background-color: yellow; } input:blank { background-color: yellow; }


Add PostCSS Blank Pseudo to your project:

npm install postcss css-blank-pseudo --save-dev

Use it as a PostCSS plugin:

const postcss = require('postcss'); const postcssBlankPseudo = require('css-blank-pseudo'); postcss([ postcssBlankPseudo(/* pluginOptions */) ]).process(YOUR_CSS /*, processOptions */);

PostCSS Blank Pseudo runs in all Node environments, with special instructions for:

NodePostCSS CLIWebpackCreate React AppGulpGrunt



The preserve option determines whether the original notation is preserved. By default, it is preserved.

postcssBlankPseudo({ preserve: false }) input:blank { background-color: yellow; } /* becomes */ input[blank].js-blank-pseudo, .js-blank-pseudo input[blank] { background-color: yellow; }


The replaceWith option determines the selector to use when replacing the :blank pseudo. By default is [blank]

postcssBlankPseudo({ replaceWith: '.css-blank' }) input:blank { background-color: yellow; } /* becomes */ .foo { color: blue; color: red; } .baz { color: green; }

Note that changing this option implies that it needs to be passed to the browser polyfill as well.


The disablePolyfillReadyClass option determines if selectors are prefixed with an indicator class. This class is only set on your document if the polyfill loads and is needed.

By default this option is false. Set this to true to prevent the class from being added.

postcssBlankPseudo({ disablePolyfillReadyClass: true }) input:blank { background-color: yellow; } /* becomes */ input[blank], input[blank] { background-color: yellow; } input:blank { background-color: yellow; }


import cssBlankPseudoInit from 'css-blank-pseudo/browser'; cssBlankPseudoInit();


<!-- When using a CDN url you will have to manually update the version number --> <script src="[email protected]/dist/browser-global.js"></script> <script>cssBlankPseudoInit()</script>

PostCSS Blank Pseudo works in all major browsers, including Safari 6+ and Internet Explorer 9+ without any additional polyfills.

This plugin conditionally uses MutationObserver to ensure recently inserted inputs get correct styling upon insertion. If you intend to rely on that behaviour for browsers that do not support MutationObserver, you have two options:

  1. Polyfill MutationObserver. As long as it runs before cssBlankPseudoInit, the polyfill will work.
  2. If you don't want to polyfill MutationObserver you can also manually fire a change event upon insertion so they're automatically inspected by the polyfill.

Browser Usage


The force option determines whether the library runs even if the browser supports the selector or not. By default, it won't run if the browser does support the selector.

cssBlankPseudoInit({ force: true });

Similar to the option for the PostCSS Plugin, replaceWith determines the attribute or class to apply to an element when it's considered to be :blank.

cssBlankPseudoInit({ replaceWith: '.css-blank' });

This option should be used if it was changed at PostCSS configuration level. Please note that using a class, leverages classList under the hood which might not be supported on some old browsers such as IE9, so you may need to polyfill classList in those cases.



What is css-blank-pseudo?

Style form elements when they are empty

Is css-blank-pseudo popular?

The npm package css-blank-pseudo receives a total of 6,370,714 weekly downloads. As such, css-blank-pseudo popularity was classified as popular.

Is css-blank-pseudo well maintained?

We found that css-blank-pseudo demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago.It has 2 open source maintainers collaborating on the project.

Last updated on 23 Aug 2022

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