title: How to detect support for the HTML5 "download" attribute?
body: <p>One of the new features implemented in HTML5 is the <code>download</code> attribute for anchor tags. The benefit of this attribute is that it gives users the means to download content created within a client application, such as an image (converted from a canvas, for instance).</p>
  
  <p>Currently, support for this feature is very poor, so I'd like to know how can I detect support for this feature in a browser.</p>