mdn / mdn/mdn

CSS filter() function

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Description

Proposal

The filter() function in CSS takes an image and a filter. It applies the filter to that image.

For example:
background-image: filter(url(_[URL-to-image]_), blur(5px))

This has been in Safari for a decade, but was never documented on MDN.

Browser support

Safari 9.1+ (unprefixed, 9.0 with prefix)
https://caniuse.com/css-filter-function

Tasks

Documentation on MDN is what's needed.

Dependencies
Additional information

Specification: https://drafts.fxtf.org/filter-effects/#FilterCSSImageValue

Web Platform tests: https://wpt.fyi/results/css/filter-effects/filter-function?label=master&label=experimental&aligned

Interop 2026 proposal: https://github.com/web-platform-tests/interop/issues/1160

Are you willing to support this work?

No response

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the CSS Filter Effects specification, the linked Can I Use data, and the Web Platform Tests results to understand the filter() syntax and browser behavior. Add the missing MDN documentation for the CSS filter() function, including the proposal's example and support information, then verify it against the specification and linked tests.

Written by the indexing model from the issue text.

Assessment

Tech stack
css
Domain
documentation, web-dev
Issue type
Documentation
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
55/100

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