title: What is the MM/DD/YYYY regular expression and how do I use it in php?
body: <p>I found the regular expression for MM/DD/YYYY at <a href="http://www.regular-expressions.info/regexbuddy/datemmddyyyy.html" rel="noreferrer">http://www.regular-expressions.info/regexbuddy/datemmddyyyy.html</a> but I don't think I am using it correctly.</p>
  
  <p>Here's my code:</p>
  
  <pre><code>$date_regex = '(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d';
  
  $test_date = '03/22/2010';
  if(preg_match($date_regex, $test_date)) {
    echo 'this date is formatted correctly';  
  } else {
    echo 'this date is not formatted correctly';  
  }
  </code></pre>
  
  <p>When I run this, it still echoes 'this date is not formatted correctly', when it should be saying the opposite. How do I set this regular expression up in php?</p>