Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
<script>
$(document).ready(function(){
    var treeTraversal = $("div").children().map(function(){
    return this.tagName;}).get().join(", ");
    $("div").after("<h2>" + treeTraversal + "<h2>");
});
</script>
</head>

<body>
  <div> This is a div element. My child is:  
    <p>             
      <span></span>    
    </p>  
  </div>
</body>

In this example, $("div").children will only return P, and not P + SPAN, because children() only traverse a single level down the DOM tree.

</html>