title: How to mak creditcard cvv with optional length
body: <p>I need to mask my creditcard cvv with optional length 3 or 4 .</p>
  
  <p>How can i do this?</p>
  
  <p>My code </p>
  
  <pre><code>$("#cvv").mask("9999");
  </code></pre>
  
  <p>I need to take value with 3 or 4 length.</p>
  
  <p>Thanks </p>