title: json jquery .. get value number of duplicate
body: <pre><code>// for example
  var arrayName = [1, 2, 2, 3, 4, 2];
  alert ( arrayName[2].length ); // undefined
  </code></pre>
  
  <p>What I want is</p>
  
  <pre><code>alert ( arrayName[2].length ); // 3
  </code></pre>
  
  <p>Or any other way .. thank you</p>