title: How to check if two strings contain same characters in Javascript?
body: <p>I have two strings:</p>
  
  <pre><code>var a = 'ABCD';
  var b = 'DEFG';
  </code></pre>
  
  <p>I need to compare these variables to check if there is not a common CHARACTER in the two strings.</p>
  
  <p>So for this case return <code>false</code> (or do something...) because <code>D</code> is a common character in them.</p>