title: Google Structured Data Testing Tool error "url: missing and required" for Microdata markup of logo
body: <p>I am trying to use Microdata to mark up my webpage. When I got to marking up the logo I am stuck, I keep getting the error "<code>url</code>: missing and required". Must I include a <code>url</code> when I am declaring <code>logo</code> as an item property? </p>
  
  <p>Error in the Structured Data Testing Tool:</p>
  
  <p><a href="https://i.stack.imgur.com/ydmNr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ydmNrm.png" alt="screenshot of the Structured Data Testing Tool: &#39;url: missing and required&#39;"></a></p>