title: Jquery get difference between two strings
body: <p>Hi and thanks in advance.
  Just a simple question, I have two variables:</p>
  
  <p>var x = 'abc';</p>
  
  <p>var y = 'ac';</p>
  
  <p>I would like to compare them and get the difference between them, this result:</p>
  
  <p>diff = 'b';</p>