title: php difference between am pm time in hours and minutes
body: <p>How to find the difference between these two times.</p>
  
  <p>I have two times</p>
  
  <pre><code>$start_time = '09:30 PM';
  $end_time   = '10:45 PM';
  </code></pre>
  
  <p>I want the output</p>
  
  <pre><code>1h 15m.
  </code></pre>
  
  <p>How to do with php??</p>