Attribute “datetime” not allowed on element “span” at this point

Question

I ran my webpage through validator.w3.org and it came up with three errors. I am using Schema.org/WebPage for reference.

Attribute “datetime” not allowed on element “span” at this point.

Anyone understand what they mean

<span class="alignright">
<br/>Last Modified : <span itemprop="dateModified" datetime="20-06-2022T20:39:45">20th June 2022</span><br/>
Date Published : <span itemprop="dateCreated" datetime="16-04-2014T10:38:32">16th April 2014</span>
</span>

I can't see anything wrong with this and the error is not clear.

Answer 1

datetime a valid attribute for <time> , <ins> , and <del> tags which would be semantically perfect for that layout.

<span class="alignright">
<br/>Last Modified : 
<time itemprop="dateModified" datetime="2022-06-20T20:39:45">20th June 2022</time><br/>
Date Published : 
<time itemprop="dateCreated" datetime="2014-04-16T10:38:32">16th April 2014</time>
</span>