title: schema.org product availability tags markup
body: <p>Which one is correct?</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;link itemprop="availability" href="http://schema.org/InStock"&gt;
  ​&lt;meta itemprop="availability" content="InStock" /&gt;
  &lt;span itemprop="availability" content="in_stock"&gt;&lt;/span&gt;
  </code></pre>
  
  <p>I checked official schema documentation and in examples found all of them.</p>
  
  <p>I suppose all of them will work, but at the moment, is there any preferred standard?</p>