title: Modify css style for pseudo element :after content with Jquery
body: <p>I have baloon shape designed with CSS3.<br>
  <a href="http://jsfiddle.net/PcLDM/1/" rel="noreferrer">JS Fiddle Example</a>
  It's have triangle made with </p>
  
  <pre><code>:after {
      content: "";
  }
  </code></pre>
  
  <p>I need to moving triangle left-right with modify <strong>left</strong> css param with Jquery. 
  I know that i can't select pseudo element which out of DOM, but is there another way to change :after style with js?</p>
  
  <p>Yes, we can put another div inside like</p>
  
  <pre><code>&lt;div class="pop"&gt;&lt;div class="arr"&gt;&lt;/div&gt;&lt;/div&gt;
  </code></pre>
  
  <p>but it's ugly</p>