title: setCustomValidity Bootstrap keep error popup
body: <p>I've implement localization in my application, all this stuff is saved inside a php file. So I can easy do this:</p>
  
  <pre><code>&lt;input class="form-control" type="text" required="" placeholder="username" oninvalid="this.setCustomValidity('&lt;?php echo $this-&gt;lang-&gt;line('field_required'); ?&gt;')"&gt;&lt;/input&gt;
  </code></pre>
  
  <p>Now if I doesn't enter any text I can see the custom message, but if I fill the input I see again the popup as the form can't get the text inside.</p>
  
  <p>It's a  bug of Bootstrap?</p>
  
  <p><strong>EXAMPLE</strong></p>
  
  <p><a href="https://jsfiddle.net/DTcHh/23662/" rel="nofollow">https://jsfiddle.net/DTcHh/23662/</a></p>