title: jquery background-position-x issue
body: <p>How to do background-position-x in Jquery ?</p>
  
  <pre><code>console.log($('.element').css('background-position-x'));
  </code></pre>
  
  <p>Outputs <code>(an empty string)</code></p>
  
  <pre><code>console.log($('.element').css('background-position'));
  </code></pre>
  
  <p>Outputs <code>0px 0px</code></p>
  
  <p>What I want to do is:</p>
  
  <pre><code>$(this).css('background-position-x', '-162px');
  </code></pre>
  
  <p>How to make it work ?</p>
  
  <p>Thank you very much.</p>