title: CSS Selector doesn't work as expected
body: <p>I am developing a website which relies on user input to create scripts
  As a defense in depth solution I am adding a blacklist protection to omit all links with an external source. I tried the following code snippet but it doesn't work (my browser supports it because w3schools sample works on it) :</p>
  
  <pre><code>    [href~=//]
      {
          display: none;
      }
  </code></pre>