title: CSS Filter not working in Firefox
body: <p>I am trying CSS filter but it does not work in my Firefox (15.0) browser. </p>
  
  <p>HTML:</p>
  
  <pre><code>&lt;div class="google"&gt;
       &lt;img src="https://www.google.com/images/srpr/logo3w.png"&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>CSS:</p>
  
  <pre><code>.google{   
      -moz-filter: grayscale(100%);
      filter: grayscale(100%);
  }
  </code></pre>
  
  <p>Demo:
  <a href="http://jsfiddle.net/xDJzU/">http://jsfiddle.net/xDJzU/</a></p>