title: How to do image mask on Firefox?
body: <p>I've tried to mask image with my png and it perfectly works on chrome.
  However, it doens't work on Firefox.
  Here is the style I used</p>
  
  <pre><code>-webkit-mask: url("../img/mask.png");
  -o-mask: url("../img/mask.png");
  -ms-mask: url("../img/mask.png");
  </code></pre>
  
  <p>Does Firefox support masking and how to do it?</p>