title: Blur.Js without backgroundimage?
body: <p>Im trying to make a navigation which has a alpha and blurs out whatever is behind.
  I use Blur.Js and had an error wich i fixed with the help of this side:</p>
  
  <p><a href="https://stackoverflow.com/questions/18076401/why-is-blur-js-trying-to-access-the-file-none/24112697#24112697">Why is blur.js trying to access the file &quot;none&quot;?</a></p>
  
  <p>Now i get 
  Uncaught TypeError: Cannot read property 'replace' of undefined   blur.min.js:6</p>
  
  <p>i guess the function which causes it is: </p>
  
  <pre><code>return this.each(function(){var A=l(this),I=l(e.source),B=I.css("backgroundImage").replace(/"/g,"").replace(/url\(|\)$/ig,"");
  </code></pre>
  
  <p>is there a possibilty how to fix this so i can use it without a background image?</p>