title: JQuery string contains check
body: <p>I need to check whether a string contains another string or not?</p>
  
  <pre><code>var str1 = "ABCDEFGHIJKLMNOP";
  var str2 = "DEFG";
  </code></pre>
  
  <p>Which function do I use to find out if str1 contains str2?</p>