# Exactly how much CSS3 does your browser support?

DevFeed: [Exactly how much CSS3 does your browser support?](<https://devfeed.tech/articles/exactly-how-much-css3-does-your-browser-support-52039.md>)

Original publisher: [Read original article](<https://lea.verou.me/2012/02/exactly-how-much-css3-does-your-browser-support/>)

Author: Lea Verou

Published: 2012-02-02T00:00:00Z

Content type: article

Language: en

Sources: [Lea Verou's blog](<https://devfeed.tech/sources/lea-verou-s-blog.md>)

Topics: [browser](<https://devfeed.tech/topics/browser.md>), [CSS](<https://devfeed.tech/topics/css.md>), [HTML](<https://devfeed.tech/topics/html.md>), [WebKit](<https://devfeed.tech/topics/webkit.md>), [Google Chrome](<https://devfeed.tech/topics/google-chrome.md>), [W3C](<https://devfeed.tech/topics/w3c.md>)

Tags: [blog](<https://devfeed.tech/tags/blog.md>), [border](<https://devfeed.tech/tags/border.md>), [border-image](<https://devfeed.tech/tags/border-image.md>), [browser](<https://devfeed.tech/tags/browser.md>), [browsers](<https://devfeed.tech/tags/browsers.md>), [chrome](<https://devfeed.tech/tags/chrome.md>), [css](<https://devfeed.tech/tags/css.md>), [css3](<https://devfeed.tech/tags/css3.md>), [original](<https://devfeed.tech/tags/original.md>), [releases](<https://devfeed.tech/tags/releases.md>), [w3c](<https://devfeed.tech/tags/w3c.md>), [web-standards](<https://devfeed.tech/tags/web-standards.md>), [webkit](<https://devfeed.tech/tags/webkit.md>)

## AI overview

An author describes a CSS3 test suite that measures whether browsers recognize features specified by the W3C. The project tests syntax across browser implementations, reports prefixed and unprefixed support, and aggregates results through Browserscope, while noting that syntax recognition does not guarantee correct behavior.

## Source excerpt

This project started as an attempt to improve dabblet and to generate data for the book chapter I'm writing for Smashing Book #3. I wanted to create a very simple/basic testsuite for CSS3 stuff so that you could hover on a e.g. CSS3 property and you got a nice browser support popup. While I didn't achieve that (turns out BrowserScope doesn't do that kind of thing), I still think it's interesting as a spin-off project, especially since the results will probably surprise you. How it works css3test (very superficially) tests pretty much everything in the specs mentioned on the sidebar (not just the popular widely implemented stuff). You can click on every feature to expand it and see the exact the testcases run and whether they passed. It only checks what syntax the browser recognizes, which doesn't necessarily mean it will work correctly when used. WebKit is especially notorious for cheating in tests like this, recognizing stuff it doesn't understand, like the values "round" and "space" for background-repeat, but the cheating isn't big enough to seriously compromise the test. Whether a feature is supported with a prefix or not doesn't matter for the result. If it's supported without a prefix, it will test that one. If it's supported only with a prefix, it will test the prefixed one. For properties especially, if an unprefixed one is supported, it will be used in all the tests. Only stuff that's in a W3C specification is tested. So, please don't ask or send pull requests for proprietary things like -webkit-gradient() or -webkit-background-clip: text; or -webkit-box-reflect and so on. Every feature contributes the same to the end score, as well as to the score of the individual spec, regardless of the number of tests it has. Crazy shit Chrome may display slightly different scores (1% difference) across pageloads. It seems that for some reason, it fails the tests for border-image completely on some pageloads, which doesn't make any sense. Whoever wants to investigate, I'