title: RegEx Date Validation for M/D/YYYY and MM/DD/YYYY (InfoPath)
body: <p>I'm looking for some RegEx for a custom pattern validation for a date field in InfoPath 2010. The accepted date format is m/d/yyyy or mm/dd/yyyy.</p>
  
  <p>Attempt 1: <code>(\d{1,2})/(\d{1,2})/(\d{4})</code></p>
  
  <p>Attempt 2: <code>(0?[1-9]|[12][0-9]|3[01])/(0?[1-9]|1[012])/((19|20)\d\d)</code></p>
  
  <p>Had better luck with attempt 1, and not much at all with attempt 2.</p>