title: Dynamically change parsley rules for a field
body: <p>I have a task which I can simple describe: I have a dropdown with, say, 3 positions. And one field.</p>
  
  <ul>
  <li>If option0 is selected, then no validation for a field required. </li>
  <li>If option1 is selected, then field should be numeric. </li>
  <li>If option2 is selected, then field should match some regex.</li>
  </ul>
  
  <p>How can I achieve this behaviour with <code>Parsley</code>? </p>
  
  <p>The only way I found for now is remove a whole parsley, change HTML and then reinit it:</p>
  
  <pre><code>$(myDropDown).change(function() {
      $('form').parsley().destroy();
  
      var input = $(this).parent().find(".my-cool-input");
      //changing input attributes based on selected value
  
      //reinitialize parsley
      $('form').parsley();
  });
  </code></pre>
  
  <p>But here I change global state of whole parsley while I want to change one field validation only.</p>
  
  <p>Another option is writing a custom validator, but I want to reuse standard email and others validation rules and messages, if possible. </p>