Unregistered values of rel attribute in anchor tag

Question

I used rel values in jQuery for the parametrized (#!hashbang) AJAX calls.

<a id='_qualifier' rel='telephony' href='contact.php'>contact</a>

and with jQuery:

var hashbang = "#!"+$("#_qualifier").attr('rel'); //gives desired result=>"#!telephony"

But, when I validated the page on validator.w3.org, it gave me error:

Bad value #telephony for attribute rel on element a: Keyword #telephony is not registered.

I searched around and according to the HTML5 specs here and here, the rel attribute should have the registered/pre-defined values.

1. Is there a work around to use custom values for rel in HTML5, without failing the validation?
2. Is it also invalid for HTML4 doctypes?

Answer 1

You can use custom attributes:

<a href="#" data-something="telephony">...</a>

It is HTML5 compliant, but not HTML4 or xHTML. You'll access the attribute just like you did with jQuery.

You can find more informations on the HTML5 reference.

Answer 2

Is there a work around to use custom values for rel in HTML5, without failing the validation?

The microformats page is a Wiki. If you are satisfied that you are using rel correctly and that there is no other appropriate rel value already registered, you can add you own value as a Proposed value. Instructions for doing so can be found here: http://dev.w3.org/html5/spec/links.html#other-link-types

According to the HTML5 spec, this will make your rel value valid. Of course, it may take some time before automated validators catch up with this, but that's just a technical matter.

Is it also invalid for HTML4 doctypes?

No, it isn't.