title: php get microtime from date string
body: <p>I am trying to get the time passed between two datetime strings (including milliseconds)</p>
  
  <p>example:</p>
  
  <pre><code>$pageTime = strtotime("2012-04-23T16:08:14.9-05:00");
  $rowTime = strtotime("2012-04-23T16:08:16.1-05:00");
  $timePassed = $rowTime - $pageTime;
  echo $timePassed . "&lt;br/&gt;&lt;br/&gt;";
  </code></pre>
  
  <p>What I want to see echoed is "1.2" but <code>strtotime()</code> ignores the millisecond part of the string.  Also, apparently <code>microtime()</code> doesn't let you give it a datestring... Is there an alternative function for calculating this, or am I going to have to do some string parsing to extract the seconds and milliseconds and subtract?</p>