title: How to alternate style (background color ) for div inside div
body: <p>How to alternate style (background color with jquery) for div inside div with id="container" alternately ( even and odd ) if I have HTML like this  </p>
  
  <pre><code>&lt;div id="container"&gt;
     &lt;div&gt;&lt;/div&gt; 
     &lt;div&gt;&lt;/div&gt;
     &lt;div&gt;&lt;/div&gt;
     &lt;div&gt;&lt;/div&gt;
  ...
  &lt;/div&gt;
  </code></pre>
  
  <p>I know with table like </p>
  
  <pre><code>#tbl_users tr:nth-child(even) {background: #CCC;}
  #tbl_users tr:nth-child(odd) {background: #FFF;}
  </code></pre>
  
  <p>but how to div apply something like this ?</p>