CSS Validator to report vendor-specific extensions as warnings, not errors

In late 2009 I wrote an article explaining that Vendor-specific extensions are invalid CSS. They are also a fact of life if you want to be able to use new CSS features, which most of us do.

As I explain in the article, the CSS Validator reporting vendor-specific extensions as errors is correct, but it does make it difficult to find any real errors (typos, syntax errors, etc.) among all the “Property -webkit-border-radius doesn’t exist” and similar messages. And as we add more and more vendor-specific selectors in order to use CSS3, this situation gets worse.

I suggested that the CSS Validator could somehow let you know if the errors are caused by vendor-specific extensions or if they are actual syntax errors. Well, something similar to that will soon be possible since CSS Validation Will Soon Be More Realistic.

An update to the CSS Validator adds an option called “Vendor Extensions” where you can choose to have it report vendor extensions as warnings, not errors. Excellent! This has two benefits:

  • The list of errors will now contain (hopefully) only things that you should do something about, making it less likely that you leave typos and mistakes in your CSS.
  • Vendor extensions will be reported as “Property -webkit-border-radius is an unknown vendor extension” instead of “Property -webkit-border-radius doesn’t exist”.

The update hasn’t been applied to the validator at http://jigsaw.w3.org/css-validator/ yet, but you can test it on the development version of the W3C CSS Validator.

Posted on January 26, 2011 in CSS

Comments are disabled for this post (read why), but if you have spotted an error or have additional info that you think should be in this post, feel free to contact me.