title: Can you blur the content beneath/behind a div?
body: <p>I'm creating a new web design in Photoshop at the moment, but I'd like to know if it's possible to blur the content beneath a div?</p>
  
  <p>I'd like to create a half transparent <code>nav</code> bar on my page that's fixed at the top of your screen. Everything that flows beneath/behind, I want to have blurred. For those of you that have an iDevice with iOS 7, check out Safari's header; where the page beneath the header is blurred. That's the effect what I'm looking for.</p>
  
  <p>I wouldn't mind the effect not working on older browsers (IE8 etc.), which in that case will have a 0.5 opacity white background as fallback.</p>
  
  <p>If this is possible, I'm really looking for the necessary code!</p>