title: How to create a DateInterval from a time string
body: <p>If I have a time format string like "14:30:00" ("hours:minutes:seconds"), how do I get a DateInterval from the string?  </p>
  
  <p>I can get a DateTime:  </p>
  
  <pre><code>$datetime= DateTime::createFromFormat("H:i:s","14:30:00");
  </code></pre>
  
  <p>But I need to add it to another DateTime object, and date_add needs a DateInterval.</p>