title: php date format regex check
body: <p>i am trying to valdiate the date field "<code>YYYYMMDD</code>" using PHP regex. I tried something like this </p>
  
  <pre><code>/([0-9]{4})([0-9]{2})([0-9]{2})/
  </code></pre>
  
  <p>but in this one, it's going to accept any two digits like 01-99 for MM or DD, but i am looking to have something for 01-12 for MM and 01-31 for DD. Any advise on doing this?</p>
  
  <p>thanks</p>