Automatic Method:

You should now simply use: http://jigsaw.w3.org/css-validator/check/referer?profile=css3

Manual Method:

Typically if you want to dynamically link to a W3C Valid CSS page, we use this link:

http://jigsaw.w3.org/css-validator/check/referer

That’s perfect if you’re using ALL CSS2.1 as that’s the default checker, but if you implement even 1 CSS3 style you’ll fail validation. So, we can no longer use the referer method until CSS3 becomes highly supported to the mainstream.

So, as a compromise, instead of linking our pages to the referer link, we’ll have to link our stylesheet to the CSS3 Validator like so:

<a href="http://jigsaw.w3.org/css-validator/validator?uri=http://www.website.com/css/style.css&profile=css3">Valid CSS</a>

(remember to use & amp; with no spaces between & and amp; in place of & so you don’t break XHTML Validation)

With a little PHP magic we could generate the current page URL dynamically in place of:

http://www.website.com/css/style.css

But, you might find this difficult from the footer.php, if someone could re-work the following code to work properly when using a dynamic footer.php file please share:

<a href="http://jigsaw.w3.org/css-validator/validator?uri=http://<?php echo $_SERVER["HTTP_HOST"] ?><?php echo $_SERVER["REQUEST_URI"] ?>&profile=css3″>Valid CSS</a>

Thanks, Bryan