title: How can I create a mask on an HTML Object?
body: <p>I have seen in the apple site their big-images gallery in this link (for example):</p>
  
  <p><a href="http://www.apple.com/imac/" rel="nofollow">http://www.apple.com/imac/</a></p>
  
  <p>What attracted my eyes was that they sort-of masked these images so they will not be displayed outside the gallery box. In flash/as3 it is quite simple to mask an object - but how did they do it in the web?</p>
  
  <p>How does it work?</p>