title: Regular expression to validate different dates
body: <p>I have the below regular expression to validate date:</p>
  
  <pre><code>^([0]?[1-9]|1[0-2])/([0-2]?[0-9]|3[0-1])/20\d{2} ?(([0]?\d)|(1[0-2])):[0-5]\d(:[0-5]\d)? ?(AM|am|PM|pm)$
  </code></pre>
  
  <p>This is validating date as : <code>mm/dd/yyyy HH:MM:SS am</code>.</p>
  
  <p>But some customers has got the different date format for ex: <code>mm-dd-yyyy HH:MM:SS am.</code></p>
  
  <p>can somebody advise how to change my regular expression to match all formats?</p>