title: How to test if selector exists in CasperJS?
body: <p>I know I can use:</p>
  
  <pre><code>casper.test.assertExists(#selector);
  </code></pre>
  
  <p>But I want to actually store if it exists in a boolean variable.</p>
  
  <p>I.e. something like this:</p>
  
  <pre><code>var exists = SelectorExists(#selector);
  </code></pre>