Title: W3C markup validation error
Last modified: August 24, 2016

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# W3C markup validation error

 *  [lencw](https://wordpress.org/support/users/lencw/)
 * (@lencw)
 * [11 years ago](https://wordpress.org/support/topic/w3c-markup-validation-error/)
 * The following is identified as an HTML5 error in the W3C validator:
 * Attribute xmlns:v not allowed here.
    …s:v=”[http://rdf.data-vocabulary.org/#”>&lt](http://rdf.data-vocabulary.org/#”>&lt);!–
   Breadcrumb NavXT 5.2.1 –> <a titl…
 * I have tracked it down to this code in the NavXT widget:
    <div class=”breadcrumbs”
   xmlns:v=”[http://rdf.data-vocabulary.org/#”&gt](http://rdf.data-vocabulary.org/#”&gt);
 * Is there a way to fix this, and more importantly what’s the purpose of this URL
   when all this plugin is doing is providing a breadcrumb from pages within the
   site? I don’t see why it needs external resource or reference.
 * [https://wordpress.org/plugins/breadcrumb-navxt/](https://wordpress.org/plugins/breadcrumb-navxt/)

Viewing 3 replies - 1 through 3 (of 3 total)

 *  Plugin Author [John Havlik](https://wordpress.org/support/users/mtekk/)
 * (@mtekk)
 * [11 years ago](https://wordpress.org/support/topic/w3c-markup-validation-error/#post-6180839)
 * This is part of the RDFa breadcrumbs specification: [https://developers.google.com/structured-data/breadcrumbs](https://developers.google.com/structured-data/breadcrumbs)
 * If you would like to remove it when using the widget, change the “Output trail
   as:” widget option to “Plain”. Note, you may want to remove the other components
   relating to RDFa breadcrumbs from your breadcrumb templates (in the Breadcrumb
   NavXT settings page).
 *  Thread Starter [lencw](https://wordpress.org/support/users/lencw/)
 * (@lencw)
 * [11 years ago](https://wordpress.org/support/topic/w3c-markup-validation-error/#post-6180908)
 * Thanks, that has worked. So if I understand this correctly, we can activate the
   RDFa structure as suggested by Google and have errors in the W3C validation, 
   or have valid HTML and no RDFa. I am now interested to know which way round is
   of more value to the website, until the recent RDFa in HTML5 I have just been
   reading about is implemented. Can someone advise please.
 *  Plugin Author [John Havlik](https://wordpress.org/support/users/mtekk/)
 * (@mtekk)
 * [11 years ago](https://wordpress.org/support/topic/w3c-markup-validation-error/#post-6180910)
 * My understanding is the the RDFa xmlns:v tag propery is deprecated, but still
   supported for backwards compatibility in xHMTL served as text rather than XML(
   silly and quite arbitrary distinction between the two serving methods). For HTML5,
   it was supposed to be supported, but again not recommended. The W3C validation
   tool likely either reports the deprecated use as “invalid” even though it technically
   isn’t. Then again, I haven’t bothered with the W3C validation tool since moving
   away from static, hand edited, HTML/xHTML to using a CMS.
 * Ideally, we’d use the Schema.org microformat markup (does not have this issue),
   but that breadcrumb syntax isn’t supported by Google yet. In the end, I don’t
   think it really matters either way. Google doesn’t actually need the RDFa markup
   to determine what is a breadcrumb trail.

Viewing 3 replies - 1 through 3 (of 3 total)

The topic ‘W3C markup validation error’ is closed to new replies.

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 * 3 replies
 * 2 participants
 * Last reply from: [John Havlik](https://wordpress.org/support/users/mtekk/)
 * Last activity: [11 years ago](https://wordpress.org/support/topic/w3c-markup-validation-error/#post-6180910)
 * Status: not resolved