title: Differentiate between indexOf 1 and 11
body: <p>Can some one please tell what should I do to get this:</p>
  
  <p><code>"1,2,11".indexOf("1") != -1</code>  as true, but</p>
  
  <p><code>"0,2,11".indexOf("1") != -1</code>  as false</p>
  
  <p>I want 11 to be taken fully.</p>