2.6 KiB
CSS Blank Pseudo 
CSS Blank Pseudo lets you style form elements when they are empty, following the Selectors Level 4 specification.
input {
/* style an input */
}
input:blank {
/* style an input without a value */
}
Usage
From the command line, transform CSS files that use :blank selectors:
npx css-blank-pseudo SOURCE.css --output TRANSFORMED.css
Next, use your transformed CSS with this script:
<link rel="stylesheet" href="TRANSFORMED.css">
<script src="https://unpkg.com/css-blank-pseudo/dist/browser-global.js"></script>
<script>cssBlankPseudo(document)</script>
⚠️ Please use a versioned url, like this : https://unpkg.com/css-blank-pseudo@3.0.0/dist/browser-global.js
Without the version, you might unexpectedly get a new major version of the library with breaking changes.
⚠️ If you were using an older version via a CDN, please update the entire url. The old URL will no longer work in a future release.
That’s it. The script works in most browsers.
How it works
The PostCSS plugin clones rules containing :blank,
replacing them with an alternative [blank] selector.
input:blank {
background-color: yellow;
}
/* becomes */
input[blank] {
background-color: yellow;
}
input:blank {
background-color: yellow;
}
Next, the JavaScript library adds a blank attribute to
elements otherwise matching :blank natively.
<input value="" blank>
<input value="This element has a value">
⚠️ :not(:blank)
with option : preserve true
input:not(:blank) {
background-color: yellow;
}
/* becomes */
input:not([blank]) {
background-color: yellow;
}
input:not(:blank) {
background-color: yellow;
}
When you do not include the JS polyfill one will always match in browsers that support :blank natively.
In browsers that do not support :blank natively the rule will be invalid.
currently no browsers support :blank