title: Array inside Array and $.map()
body: <p>I try to learn <a href="http://api.jquery.com/jQuery.map/" rel="nofollow">jQuery.map()</a> and something i misunderstand</p>
  
  <p>Why...</p>
  
  <pre><code>var arr = [0];
  arr = $.map(arr, function(a,i) {
    return [a,i];
  });
  </code></pre>
  
  <p>Return <code>[0, 0]</code>
  ,Why not <code>[[0,0]]</code></p>
  
  <p>but normally</p>
  
  <pre><code>var arr = [0];
  arr = [arr,0];
  </code></pre>
  
  <p>Return <code>[[0], 0]</code></p>
  
  <p><a href="http://jsbin.com/uhixex/1/edit" rel="nofollow">http://jsbin.com/uhixex/1/edit</a></p>
  
  <p>Seems like stupid qustion, But expain me pls</p>