title: How do I test if HTML5 validation was triggered for a required field with Selenium?
body: <p>Let say I have the following snippet of HTML5:</p>
  
  <pre><code>&lt;form method="get" action="logginValidation.php"&gt;
      &lt;input type="text" required="" name="username"&gt;
      &lt;button class="btn" type="submit"&gt;Se connecter&lt;/button&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>Using Selenium, I leave the field empty and press the button.
  The form is not validated as I would expect, but how can I verify that <strong>this</strong> field is invalid and that there's an associated message with <strong>this</strong> field.</p>
  
  <p>Now one thing I haven't investigated is that I'm using Twitter Bootstrap with the JavaScript libraries loaded. I have to double check if those librairies aren't playing tricks on me and that the validation is really coming from the Firefox browser.</p>