title: Password REGEX with min 6 chars, at least one letter and one number and may contain special characters
body: <p>I need a regular expression with condition:</p>
  
  <ul>
  <li>min 6 characters, max 50 characters</li>
  <li>must contain 1 letter</li>
  <li>must contain 1 number</li>
  <li>may contain special characters like !@#$%^&amp;*()_+</li>
  </ul>
  
  <p>Currently I have pattern: <code>(?!^[0-9]*$)(?!^[a-zA-Z]*$)^([a-zA-Z0-9]{6,50})$</code></p>
  
  <p>However it doesn't allow special characters, does anybody have a good regex for that?</p>
  
  <p>Thanks</p>