title: Change the style of :before and :after pseudo-elements?
body: <p>This is what my code looks like:</p>
  
  <pre><code>$('.mainSpan:before').css('background','url(_gfx/cmn/main_bg.png)');
  </code></pre>
  
  <p>This does not seem to work so I'm asking if it's even possible to add 
  background images to shadow elements with jQuery.</p>