title: Empty attribute selector not working in Edge browser
body: <p>I'm using a specific version of Edge where the empty attribute selector is not working (more information <a href="https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/13197805/" rel="nofollow noreferrer">here</a>)</p>
  
  <p>My selector looks like this:</p>
  
  <pre><code>[ct-validation]:not([ct-validation=""]) {
    border-color: red;
  }
  </code></pre>
  
  <p>The <code>ct-validation</code> attribute contains an error message. If the error message exists, then a red border is applied to the element. This works fine in all browsers except for Edge (40.15063.0.0). Upgrading is not an option due to Corporate IT restrictions :(</p>
  
  <p>Is there a different way to check that an attribute is empty with using CSS <strong>only</strong>?</p>