title: How to add 'required' validation to aui:input dynamically from js
body: <p>here is aui:input</p>
  
  <pre><code>&lt;aui:input name="price" id="price" showRequiredLabel="false" value=""&gt;
    &lt;aui:validator&gt;
      // I have some custom validator for price format
    &lt;/aui:validator&gt;
  &lt;/aui:input&gt;
  </code></pre>
  
  <p>I have a radio button group. on click of one of those radio buttons, I want to apply required aui validator dynamically. I tried adding <code>required=true</code> from js, that works but as a 'HTML5 required' validation. I want to achieve this through AUI validation.</p>