W3 markup validation fails

Hello,

it is the same to me.

I was also looking for a support post about this.

Line 9, Column 13112: Bad value lightbox-0 for attribute rel on element a: The string lightbox-0 is not a registered keyword.
…e-cottages-beach.jpg" rel="lightbox-0"><img class="size-medium wp-image-247" s…

It turns out the lightbox keyword is just proposed so far, and not yet officially adopted, so that’s probably why the validation service complains.

https://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions

This is (unfortunately) a very well known problem.

In the past – which means before HTML5 – “rel” was not very specific and you could put nearly anything to this attribute.

But now “rel” has a specific meaning and you can not put anything in it you want. The valid way is to use “data-rel” and not “rel”.

You may safely ignore this – it will still work.

I proposed a modification which may allow to choose “data-rel” instead of “rel” – but I’m not sure when (or if) this will ever make it to the plugin.

If you want to fix this, you need to change the code – I did this on my own for “Swipebox” (the other ones are not that easy – but the general way is the same).

1) In responsive-lightbox/responsive-lightbox.php, the backend part:

Changed all occurances of rel= to data-rel=.

2) In wp-content/plugins/responsive-lightbox/js/front.js, the frontend JavaScript of “Swipebox”:

Changed all occurances of rel to data-rel – but don’t just do a “search & replace”, since there is also the “preload” in the script and you don’t want to change “preload” to “pdata-reload” ??

Disclaimer: All modifications on your own risk!

Update: The same procedure also applies to the latest version of this plugin if you want to have valid HTML.

And by the way: wp-content/plugins/responsive-lightbox/js/front.js is of course not specific to “Swipebox” – it’s the plugins global front end script.

1 x Bad value lightbox error
1 x Element dl is missing a required instance of child element dd.
(per picture)

1 x Element style is missing required attribute scoped.
(per post with pictures)

In the upcoming 1.5.2 release we’re switching from rel attribute to data-rel attribute – that solves all the possible W3C validation issues.

Rel will work as it used to do, to keep compatibility with custom code in users themes, but RL will natively output data-rel.

@hlanggo, only first element you mention is RL related.

Regards,
Bartosz / dfactory

@ dFactory, thank you for the correction. I will inform two theme-makers about:

1 x Element dl is missing a required instance of child element dd.
(per picture)

1 x Element style is missing required attribute scoped.
(per post with gallery)