title: Bootstrap number validation
body: <p>I'm having Bootstrap and I have problem with validation. I need input only positive integer. 
  How to implement it?</p>
  
  <p>For example:    </p>
  
  <pre><code>&lt;div&gt;                       
      &lt;input type="number" id="replyNumber" data-bind="value:replyNumber" /&gt;
  &lt;/div&gt;
  </code></pre>