title: schema: invalid value for datetime
body: <p>I followed the instructions on <a href="https://schema.org/openingHours" rel="nofollow">schema.org</a> to add the business hours of a company in their website, however, the W3C's <a href="http://validator.w3.org/" rel="nofollow">HTML validator</a> does not like it >_&lt; It's giving me the following error: </p>
  
  <p><strong>Bad value Mo-Fr 09:00-19:00 for attribute datetime on element time: The literal did not satisfy the time-datetime format.</strong></p>
  
  <p>Below is my <strong>HTML</strong>:</p>
  
  <pre><code>&lt;div&gt;
      &lt;p&gt;Office Hours:&lt;/p&gt;
      &lt;p&gt;&lt;time itemprop="openingHours" datetime="Mo-Fr 09:00-19:00"&gt;Monday-Friday: 9:00 am to 7:00 pm&lt;/time&gt;&lt;/p&gt;
      &lt;p&gt;&lt;time itemprop="openingHours" datetime="Sa 10:00-17:00"&gt;Saturdays: 10:00 am to 5:00 pm&lt;/time&gt;&lt;/p&gt;
      &lt;p&gt;&lt;time itemprop="openingHours" datetime="Su 11:00-16:00"&gt;Sundays: 11:00 am to 4:00 pm&lt;/time&gt;&lt;/p&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>What am I doing wrong?</p>