JSON to Array (or how to know number of json objects)

JSON to Array (or how to know number of json objects)

HI, I am writing this code

  1.  <script type="text/javascript">
  2.             $(document).ready(function() {
  3.                 var obj = jQuery.parseJSON('{"a":"sss","b":"sss","question":"whi?"}');
  4.                 //alert(obj.question);
  5.                 
  6.             });
  7.   </script>
how could i know how many objects variable obj has?