I know at least 2 ways to define mainEntityOfPage
:
<div itemprop="about" itemscope itemtype="http://schema.org/Product">
<link itemprop="mainEntityOfPage" href="http://example.com/article-1" />
</div>
and
<div itemprop="about" itemscope itemtype="http://schema.org/Product">
<meta itemprop="mainEntityOfPage" content="Mycontent" itemscope itemType="https://schema.org/WebPage" itemid="http://example.com/article-1"/>
</div>
Both ways are succesfully validated. The questions are:
Which way is more optimal/universal/recognizible for search engines?
If I markup them both simultaneously is it ok? (Validator gives no errors.)